I think not all kinds of hate towards certain groups are deserving of a "phobia" label. That's how we got all the silly claims of things like "fatphobia" and "acephobia". If I irrationally hate all blondes, are we going to call it "blondephobia"?

I think the distinction between what gets to be a phobia and what doesn't is whether it's a real, active phenomenon in society. Can people hate bisexuals for reasons other than homophobia? Yes. Is it a widespread phenomenon like homophobia---which is a deep-seated issue in most people---deserving of its own name? Does it warrant specific study? I don't think so.

As far as lesbophobia, I think that homophobia just manifests differently when it's directed towards females than when it's directed towards males.

I read an interesting comment by a lesbian saying she used the word "lesbophobia" to describe the unique thing that lesbians face which she called "a mixture of homophobia and misogyny". But I think that "misogyny" is inherent in homophobia against females the way "misandry" is inherent in homophobia against males. Homophobia seems to me to be an issue of het/bihet people feeling like "ew, you aren't being a man/woman correctly". Some people would interpret the female version of that as misogyny, but to me, the different manifestations of homophobia, which I guess in this language scheme would be described as "gayphobia" and "lesbophobia" are two sides of the same coin.