As a colour-blind gamer, I can't recall having many eye-rubbing hangups over which side to attack, who was friend or who was foe. You don't need colours to tell the opposite side in a game like Star Wars: Battlefront, for example, and the only way to miss red versus blue in Halo would be to lack all colour vision. And Guitar Hero is more about finger position than it is the hue of the button to push.
That said, it's a common condition and as Ars Technica points out, one that developers either don't know what to do with, or do too little to accommodate.
Battlefield 2142, for example (I don't play it) has real problems helping color-blind gamers differentiate team flags. Puzzle games are a hard-hit genre too. And in others there are other minor issues, such as a Mario and Luigi looking almost identical to some red-green colour-sight challenged. So just to get started on a thought provoking note, and because "this is what stuff looks like to colour-blind people" is always cool, here's the article.
As for me, I don't want your pity. Seriously, I have no frame of reference to make me know I'm missing something, and I haven't yet screwed the pooch in team play (Unless you count the time in church league hoops, when we had green jerseys and Maple Springs Methodist had red, and I had to sit the bench the whole game) And who's to say you're not seeing the world all screwed up, and I'm right?
Color-blind gamers: common. Developer awareness? Minimal [Ars Technica]