I have had just the same kind of hostility as a bisexual on gay lists, and the same kind of comments - "you haven't found what you really are," "you're really gay/str8 but you won't admit it." It seems that some people are deeply attached to their personal categories, to the point where they feel threatened by anyone who seems to suggest that those categories aren't as absolute as they want to believe.
Men for whom "being a man" is basic feel threatened by gays (and don't even mention TVs). Gays who care about "gay identity" feel threatened by bis. People whose indentity is bound up in their couple relationship feel threatened by polys. Doms who believe that "some are born to rule and some to serve" feel threatened by switches. And so on.
Rimmer: "I am what I am and that's all that I am." I think Descartes said that.
Kryten: No, Sir, that was Popeye.
Rimmer: I knew it was one of those philososphers.