I'll quote myself: "I believe it's to be user freindly rather than be realistic"
They are colored for ease of identification from a distance. Like elites ranks are colored...Ahhhhh ok this makes no send a modern-day military forces are all confused because they have no color coordination to tell who is who.
I don’t mind the choice of color at all but I can see where you are coming from.
I believe it’s to be user friendly rather than be realistic. Reaslistically speaking a lot of things shouldn’t be how they are. All Spartans should technically be of same uniform, organized into squads and be constantly watched... deployed only in spec ops... etc
User freindly to the player, and not to the other troops in battle.
You have quite a point here, its not realistic at all to go full body paint different color. Someone else mentioned a couple of interesting takes that I approve of that kind of comprimise a bit. For example... using secondary colors to differentiate them. Number tags on chest... can also go a long way. Weapon of choice can also go a very long way. Maybe different colors... but not so much as to go with an entirely different hue than green. Black seems to actually make a little sense. Greyish green also makes sense. Olive as well... etc etc.
If there should be other hues... maybe coloration needs to be less vibrant... more greenish/grey...
But for the record... it doesnt really matter what color they are because the enviroments they fight in are not primarily in vegitated areas. They were intended to fight rebellion. I expect that to be in city regions? The only reason they would be colored green would be to inform others of a military presence... which works to inform players... and to inform civiliians in game.
The number tags on the chest are canon, and I wish that would have remained constant throughout the games. They're seen in Forward Unto Dawn, Halo Legends, and a few other places if I recall. Now with Infinite, it looks like the numbers printed on the armor have returned, of which I am in favor.
Really any Earth-tone color would suffice depending on the environment. Browns, grays, blacks, greens, and even some blues can be useful for camouflage. But as I said before, you have to consider the cool factor when talking about games. From a real-world perspective, Earth-tones are useful. From a game play perspective, different colors can be cool. And the "rule of cool" is very important in games.
While you have a point about the fact that the Spartans were intended to squash rebellions, it's important to note that the rebels were found in more places than just urban environments. The first major encounter with the Innies for John was on an asteroid. He also fought rebels in forests and other non-urban environments. However, I do agree that the colors matter little simply from the fact that Spartans are so effective and fast that the colors would barely register to a rebel in the middle of a battle.