Well, I wouldn't call it homophobic, because in all honesty, you have nothing against homosexuality right? And it's not really the issue here, I think.
On one hand it is understandable that you would react differently than with a girl, because the "norm" in society is that a girl and a boy fall in love, so it wouldn't be unheard of two good friends of the opposite sex start liking each other. Heterosexual love and attraction is "normal", and however "liberal" and "open-minded" we see ourselves as, when personally confronted with love, feelings and desires that "deviant" or against the norm, we react.
You never expected anything like this, so do you maybe feel betrayed? Mislead? Perhaps you even feel disappointed or afraid that your friendship meant more to you, and maybe wasn't anything else than an attempt to seduce you? I'm trying to ask you questions you have to answer, because you have to think real hard about why you reacted like you did. It will help you deal with your own feelings and hopefully be able to move on.
Now, even if your reaction is understandable from a certain perspective, I don't think it is acceptable. Sometimes we have to put ourselves in the other person's shoes. Just because your friend fell in love with you, doesn't mean your friendship didn't mean the world to him. How long to you think he kept his unrecruited love for you a secret? Have you ever loved someone, but that someone never saw you that way? It hurts, deeply, so much that he one day decided after such a long time despite everything to risk your friendship and "confess" to you (sounds a bit corny, but isn't love corny sometimes?).
In the end, when it comes to love gender doesn't really matter. Isn't love most often an extension of a friendship? Had the guy been a woman, maybe you would've thought about it and given it a chance? But because he was a guy, you couldn't deal with it and from what I read, I don't think you dealt with it in a mature way.
Perhaps you wouldn't be able to continue being as close, it would be too "weird" for you and too painful for him. But to just cut him off, and never actually talking about it most surely hurt both of you. You both lost a good friendship, and he most surely was hurt that it ended with worst case scenario once he confessed his feelings to you. I definitely think you should contact him and ask him for you to talk things through, maybe you can still be friends albeit not that close. Or maybe it will give both of you some kind of closure.
Wow. Who are you? I've failed to read your posts properly before this. That was a mistake.
I agree with everything you said. I did feel betrayed, and all of the other things you mentioned.
I think I have nothing against homosexuality. I know this is weak support for saying that, but I have close gay friends. I love them and would defend them with my life if push came to shove. But these are friends whose sexuality I have known almost from the start. I think perhaps my reaction would have been different to my best friend, if he had revealed his bisexuality to me earlier. The shock of feeling that I did not know this person at all, when he did eventually come out, perhaps contributed to my reaction.
I have no doubt that I reacted like an emotional retard. I can't meet my friend again because I wouldn't know how to explain my immediate reaction to him, nor my continued absence. I wouldn't know where to begin. And one of the reasons why I can't explain it to him is because I cannot justify it, nor understand it myself.