I think WoW acts as a trigger for his Anger Management....
Now not saying you did anything wrong, but in almost every MMO out there, there is always one particular thing that ticks off everyone, in WoW, it is the unbalance of classes....
....ok, ill toss it out there, I PLAY WoW!
Back to the issue, in WoW specifically, your brother probably has issues with the opposing side, (in this case the Alliance) and probably has ran into the alliance a few times and gotten grieved by them.
Does this constitute his anger towards you now that you are rolling an alliance? Absolutely not, hell it should be entertaining, but unfortunately, he takes it a little bit too seriously. I cant offer you much advise than this:
- Play your alliance but make sure not to say anything that might trigger his zealous "Horde Rules" anger issues like "Horde Sucks" or something along those lines.
- Tell him that just because you are playing alliance that it shouldnt affect your brotherly relationship (or some shit like that), its just a game, he needs to relax a little, despite how much he might be grieved by others.
I dunno, there are a lot of shitheads out there in WoW...and most of the internet, hell, people here who say shit about WoW would probably florish in it.