Now before you rant about how they are supposed to be bright for many reasons (like during the day), but at night the lights are blinding, LED or not
Red and Yellow seem to be at appropriate brightnesses any time of the day, but Green on the other hand is just like BOOM! and physically hurts my eyes when driving at night then approaching a Red light, and the light turns Green as soon as I'm like 200ft or so away from the light, that hurts badly
Anyway my point is why don't the dim the lamp down by like 75% or something, and yes I'm aware that green will always appear brighter but for real if the Green light was on for a long time and I was standing 50ft away, I could handwrite a paper under it
But seriously, why does the Green light need to be so bright

Our LED traffic lights are blindery bright at night as well:
1. https://www.lighting-gallery.net/gallery/displayimage.php?pos=-121268
2. https://www.lighting-gallery.net/gallery/displayimage.php?pos=-87495
3. https://www.lighting-gallery.net/gallery/displayimage.php?pos=-83219
Their viewing angle is very concentrated, so they can't be viewed well from the side.
Our incandescent traffic lights are much dimmer.
I think that the controller should dim them at dusk and brighten them at dawn, so their brightness would be utilized to better visibility during full daylight, but won't blast your vision.
Most of our traffic lights are of Siemens.

The LED flashing beacons on emergency vehicles are very bright at night also. I had to pull over to the side of the road and stop completely when an ambulance was coming towards me once, its lights were so bright. I was on the opposite carriageway and did not have to pull over to make way for it, but if I hadn't stopped, they would have come across another accident a lot sooner than they'd imagined  

The LED flashing beacons on emergency vehicles are very bright at night also. I had to pull over to the side of the road and stop completely when an ambulance was coming towards me once, its lights were so bright. I was on the opposite carriageway and did not have to pull over to make way for it, but if I hadn't stopped, they would have come across another accident a lot sooner than they'd imagined  

I know what you mean, around here they are like that too. They can cause temporary blindness if there are no other lights around (like streetlights). I don't get how they are even legal.

The LED flashing beacons on emergency vehicles are very bright at night also. I had to pull over to the side of the road and stop completely when an ambulance was coming towards me once, its lights were so bright. I was on the opposite carriageway and did not have to pull over to make way for it, but if I hadn't stopped, they would have come across another accident a lot sooner than they'd imagined  

I encountered a similar case, when I was in the private transport minibus to Carmel hospital at the winter, when we stopped at a traffic light, a police car with superglaring flashing beacons appeared near us.

Yep same problem with the green lights here in the countryside when there isn't any street lighting around. To me it's the equivalent of someone blasting you with their brights if not worse. I can see the intersection well, but nothing beyond it.

In Minnesota any intersection that has a traffic signal also has overhead street lighting. So it makes the traffic signals less bright at night relative to the background.

In some cases, this could potentially be a safety hazard... which is something I ended up finding
out the hard way a couple years ago. While I was driving, my windshield was fogging up and it was
early in the morning. I was driving to work... and I was in the turning lane. The lights
for the lanes beside me, turned green. The glare on the windshield was so incredible that I thought
I saw the green arrows for me to turn. Sooooooooooooooo, I did. *BLA BA BAM!!* Hit an oncoming car head on.
Now... had that car driver not swerved to avoid me, car damage and injury would've been severe for BOTH of us.
But luckily my car didn't get much damage. To my surprise, her SUV got the most damage. I was the one
at fault, so of course, I revealed this in the police report... but I also remember mentioning
the glare of the green light.

U.K. traffic light systems do have the facility to dim at night, at a group of traffic lights there is at least one traffic light pole with a photocell fitted to the top of it linked back to the roadside controll box to dim them all at a certain lux level, it is a system that has been around many years on both the old tungsten system and carried over to newer led installations, there are cases where the photocell has stoped working and they can be bright st night or dim during the day but largely here in the U.K. at least we have a controll system in place to prevent night glare.

Anyway my point is why don't the dim the lamp down by like 75% or something, and yes I'm aware that green will always appear brighter but for real if the Green light was on for a long time and I was standing 50ft away, I could handwrite a paper under it
But seriously, why does the Green light need to be so bright

I think the light use night time dimming, but either set improperly, or not effective at all after being converted from incandescents.
The problem is, the incandescents at reduced power loose brightness way faster than virtually any other light source. With incandescents reducing the electrical power to 30% (well within a comfortable range of a simple dimmer or halving the supply voltage) means about just barely 8% of the initial light output (that is in the ball park what is needed in the night vs day operation). To get the same from e.g. a LED, you need to reduce the power to that 8% level.
So if the controller is designed to halve the filament voltages for the night mode, installing the LEDs with a ballast following the power setting means the LED will shine at 30% of its rated power, so 4x more than intended for the incandescent.
The problem with LEDs supplied from a controller designed for incandescents is first the power adjustment may lack the setting range required to dim the LEDs to the same brightness (being able to go to 8% means way lower currents, in addition to the normally lower power consumption it becomes a problem for the dimmer, plus for an electrical diagnostic and other features, so the sets usually end up with higher power setting)
Plus many LED ballasts (the electronic ones) just keep maintaining the power, so the dimming just does not work at all with those.
On top of that is a misconception about the purpose of the dimming feature: Very often it is described just as a means to save lamp life and power (with the brightness reduction being treated as "acceptable"), what seems to be not needed anymore with LEDs, but many manuals are really do not mention the visibility and glare to becoming the main purpose of the night time dimming function (at time when the old controllers were designed, no one anticipated the "too much" brightness to become a real problem).
So to really work correctly, the signals needs a major upgrade when going to LEDs (completely different lamp supply concept, defrosting heaters and their control needs to be added,...; usually requiring even completely new wiring from the lanterns to the controller), but the city officials expect it to happen just by replacing the lamps and so prepare funds just for that. The result is too bright signals at night and impossible to dim it down further (because the used dimming system does not allow to go that deep down with power), lenses covered with snow at winter (there are no heater elements in the lanterns) and many more similar problems.

There could also be regulatory problems. I saw hints for such a situation in Germany, but making shure would require to read the relevant standards for lots of €€€.

In any case it should be no surprise that a signal designed for good visibility under broad daylight will blind when the lighting level is down to 0.01 percent of these 100,000 lux. For railway signals a nighttime dimming was standard from the beginning, and I think it is for traffic lights with LED technology absolutely necessary as well. It should speak for itself how they flare and light the street and the passing car in this photo.

There could also be regulatory problems. I saw hints for such a situation in Germany, but making shure would require to read the relevant standards for lots of €€€.

It is true, many regulations tend to be way too much exact in very deep details on how to do something (instead of what these really need).
Then I would not be surprised (and now I'm purely speculating) if some regulation document explicitly states "lamp input power is to be reduced to..." (instead of "brightness is to be reduced to...". Although the specification does make sense for the original incandescent technology, it yields ridiculous results for any other light source like LEDs or so.

A real example: In early 90's Brno officials did made "public lighting codex", a set of rules for public lighting design for Brno city. The idea was, it categorizes different street and make clear where to go on budget and where the high aesthetic quality justifies more expensive lighting, but to still avoid excessive costs.
There they did define street types according to required light quality vs operating costs, but then this codex did specify exact lamp types (for high color quality it specified the DX MVs, for roads mainly for car traffic they specified HPS with dimmer systems, for basic lighting HPS; all that based on 1990 technology and pricing in the industry).
But when MHs became available at reasonable prices, this codex didn't allowed their use, even when they offered better quality and lower running costs (given the used maintenance style - the MV reliability is not much benefit there).
It became funny, when MV's became banned - then all city center became illegal: Old lamps were worn out, so not replacing them was violation of the codex. But replacement lamps were not made anymore. Rebuilding lanterns for MH was illegal too - the codex allowed only explicitly MVs there. And city officials were busy with "politic fighting" and so it took very long time (at least two election periods) to start officially discussing an update of that codex.
Now it seems to be more flexible, but still I'm suspecting it may become problematic again. It assumes high output package lanterns like HID's or so. But if e.g. some LED variants evolve into long lower intensity stripe "road paint" lighting (some are suggesting this to replace e.g. motor road illumination on some places; but no real commercially viable product exist yet), the codex will prevent its use...

Another example: Some standard for railway signals also specifies the exact spectrum for each colour (in German this is called Farbort). It would not have been possible to use the green LEDs originally designed for street signals because they are a bit more on the blue side. In this case it has been fought true, because no one in the railway industry had an interest in paying forever the additional costs for special LEDs for such a nonsensical reason. It was not even about introducing a new hue of green, the Berlin company WSSB used in its signals green filters that produce almost the same result. Which is simply a distinctive green that nicely cuts through.

See here and here , how our Siemens LED traffic lights are very bright during the day, and superglaring at night.