I can't read other people's minds, but I will try a little.

TL;DR: times have changed.

There are a lot of political changes in the last decade that have led up to this situation and we're in a readjustment period where we're figuring out the "new normal." Liberal homophobia, which is a recent development since I graduated from high school in the Bush era, seems to revolve less around punishing same-sex attraction (which is conservative homophobia) and more around punishing lack of hetero attraction.

Gay organizations are completely controlled by the left, academia too. The support system gays and lesbians reach out to when they come of age hates them and pushes them in myriad ways to make themselves available to the opposite sex in some way- pick their poison, but they have to conform somehow.

This is coming from straight liberals, they have drafted and brainwashed a lot of homosexuals. Bisexuals are a convenient tool in the arsenal, but as far as I can tell aren't making decisions and are being subjected to the same pressures. I live in a red state so I don't get exposed to much of this personally.

If I was a lesbian, I would find it heartbreaking to see other lesbians destroying themselves and attempting to destroy each other. If I was over 25-ish, I would also have come of age in a time when straight liberal people accepted and defended me, and their support would be something I counted as a given. I would not want to believe the destructive people were actually lesbians. Anyone who is not exclusively a lesbian is a bisexual, therefore everyone breaking my heart and killing my community is a bisexual and I don't have to see them as my own people. This also presents a solution- tell the bisexuals to leave lesbians alone!

I obviously don't think that would work, because I don't think that's the problem. The issue is that homophobia has evolved and adapted to the gay liberation movement. The same power structure is being maintained through new means.