I don't really think this is fair to bash him for this.
I have a properly calibrated monitor but i also have key binds set with GCB settings depending on maps and if i'm using nvg or not. Its nothing that is illegal or hack for an unfair advantage because any user can do the same and its all within the game settings.
Yeah, any user can do the same, but how many people that play AA for fun and not for competition know how to do that? This isn't the 2.8 competitive scene where everyone that was good knew how to do it, this is 2.5 where people come to play in public servers for fun. I'm not going to get into whether it is cheating or not, but this is 2.5 and nobody is serious enough about the game to need to do such a thing. It will give you an advantage here, that's for sure.