who is mcavoy's character bigoted against

Bingo.

That wasn't him, that was his colleague in the beginning when they were sitting round in a circle.

pretty sure hes not bigoted against homosexuals. While he uses some slurs throughout the movie - I think its to make people think hes a homophobe. There were several parts of this movie where he intentionally moves himself very close to kissing a man.

in one of his hallucinations he also (or maybe his psych doc) says that anyone who isn't willing to hook up with someone of the same sex can't achieve greatness (I'm paraphrasing).

The only bigoted thing I can think of is when he's having the conversation on the plane to germany with bladesy - they are talking about sexual habits of races and he makes some comment about someone being with a black woman being bad (again paraphrasing - I can't remember exactly what he said but it was some sort of negative insult).

again - even that might have been to just mess with bladesy because he knew bladesy was into black chicks.

I think this is one of the things from the book that is translated to the film - somethign to show the way that his bipolar behavior / personality disorder makes him do and say things to mess with people in order to watch their behavior.

thats just my take. maybe I read way too much into it.

Funny how he was essentially describing himself when he was saying that very same thing about Dougie to Gus in the pub.

Bottom line----the dude just hated everybody and everything that stood in the way of getting that promotion he was trying to get. That was the other main point in the film--besides the fact that he himself was entirely tore up from the floor up, with his various addictions and self-hatreds tearing him apart.