For the same reason I don't like being called Japanese. Or why I don't like being called Itallian. How about being called a girl? Or being called a cat?

I don't like being called gay because, I am not gay.

If I were not Goth, would I want to be called such?

If I were gay, then I would not want to be called hetero.

I hope this simple explanation helps you understand that most of us are far from homophobic. Perhaps we are stereophobic (new word:P)