Now I know I'm not in his situation, but if I was in a situation where my roommate asked me to wait outside while he changed, I'd probably discuss it with them before labeling him "homophobic" and figure out if there was a different reason for which he didn't like me. People don't communicate at all. Also, I'm tired of people saying others are "homophobic" just because they're straight or "racist" just because they're white. If your roommate is uncomfortable with you perhaps you should talk to him about it because unless hes specifically targeting you because you're gay, being a little bit uncomfortable from the start doesn't make him a homophobe.
blargh ive been seeing stuff like this too much recently.
Also, I was pissed how he went about it. If he just told me he was changing roommates good for him, but he and everyone else had to go behind my back and move out when I wasn't here.