Yes.
I think it is homophobic, in the very specific and accurate sense of that word - you liked a guy - you find out he is bi - you no longer want to be involved, it is his homosexual behaviour/tendancies that have made you change your mind, nothing else.
That doesn't mean I think anyone who feels like this 'hates the gays' or wants to drive them all back into the closet and all the way to Narnia with a pitchfork.
I'd find practicing a religion (any!) a turn off, I'd go from 'yes please' to 'fuck no' if I found out a prospective shag was also religious, so yes, I'd be religionphobic in that context! It would give me the major ick, I'd back away so fast you'd see a dust cloud, thats how much I am religionphobic.
Doesn't mean I HATE religious people, it means I would choose not to be intimate with them. Phobia does not = hate, we've come to make 'homophobic' mean 'hate' when it shouldn't, we should just call those people 'bigots'.
Agoraphobic doesnt mean someone HATES the outside world it means the outside world fills them with the ick, its scary and unpleasant.
I don't believe anyone should fuck anyone they find gives them the ick, this isn't some sort of call for everyone to ignore their own likes/dislikes/boundaries/icks and fuck other people despite them... but it does mean that deep down you really really find the idea of homosexual sex revolting. Its not neutral, or you wouldn't mind, its not a turn on... so what else is it, a strong phobia of something, in this case, homosexual intercourse.
You probably also find the idea of your parents or grandparents shagging or your adult kids shagging to be equally grim, and yet you can still be in the same room as them, love them etc etc.