If a guy sleeps with a guy and hates it is he gay?

No, having sex with someone doesn't mean you are gay or straight. it could be experimenting.

I don't think so- if the reason he hates it is because of the physicality of it (vs the person or something)

A guy can sleep in the same bed with another guy without any sexual activity or penetration to occur

it depends. what drew him to have sex with a guy in the first place? was it the same guy or two different guys? if the same there are lousy lovers out there. if both were knew to the experience it could have been bad because they didn't know what they were doing. if the guy feels attracted to the guys, then just diving into sex is not necessarily the best way to explore that attraction. there are a lot of unanswered variables here.

I think there's a rule about trying things twice before it becomes gay

Impossible!! I mean for a guy to sleep with another guy and actually hate it!?!? Doesn't happen. LOL. Just teasing, but no I've never heard of that happening. Perhaps misplaced guilt led him to SAY he didn't thoroughly enjoy it?!? But, that's just MY opinion, so what do I know? Heehee.

Yes, he just had bad sex

It depends...The guy could be really bad at sex

Yes