OK, here goes.

Family is everything in China. The family values instilled by millennia of Confucianism dictates that all proper children will procreate. And the social pressure to procreate: to get married, and have a child (back when the one-child policy held sway) or multiple children (before that policy and after it) is immense.

Very few people are strong enough to resist.

So what happens in queer culture?

Well, queer or no, you will give your parents grandchildren. Which means that almost every queer person will wind up in a loveless marriage that's torture for both parties solely so that the parental demand for a grandchild is delivered.

Now some techniques have evolved for this. Like the bearded marriages. A gay couple and a lesbian couple get cross-married so officially on paper there's one man with one woman. But they live close to each other and in reality the man is married to the man and the woman to the woman. (The trans issue is ... let's just say it hasn't arrived here yet in any real strength and leave it at that.) But very few people can swing a bearded marriage. So most queer people are going to be married to someone they don't love and who will learn to hate them once the truth comes out (because it always will). Queer couples know this, at some deep level, and are resigned to it.

And into the mix come bis.

Bis can "pass" for straight. Which means that a bi woman, for example, can get into a lesbian relationship happily, but when the inevitable pressure happens, they'll scarper off, find a guy, and live happily ever after, leaving behind a lesbian who is doomed to what I mentioned earlier. (Same for bisexual men and gays.) This breeds an incredible amount of resentment, as if the bisexual is just there for a few laughs, playing with the emotions of their queer lover before running off and living the straight life. As such, bisexuals are LOATHED in local queer culture; are viewed as worse than the worst. Worse, even, than a homophobe.