I can only haphazardly guess. I'm not a psychologist or a sociologist or behaviorist or cultural expert. And it's more than likely a combination of various different intersecting reasons.

He's a narcissistic prick and an arrogant douchebag, he's almost like the stereotype of a Han ethnonationalist despite possibly not even being of Han descent.

Given that at least on paper, gender and sexuality matter less in China or its considered more of a private matter, I can understand him thinking that communists that focus on social issues (read: every legitimate communist) are wasting time debating stupid shit as China and the global south is subjugated by the imperialist West.

That doesn't whatsoever justify his bigotry and capriciousness and his false sense of arrogance.

I think that just like other Nazbols and MAGA-"communists" Xiangyu understands that something is wrong with human society. No shit, that's what being a communist means. But he misplaces blame onto anyone who isn't straight or isn't an alt-reich douchebag for daring to be different instead of just mindless drones like he is. He has probably suffered alot in life from bullying and harassment, and he thinks that is the epic kewl guy owning the libs for fighting back against "muh woke wokies!" instead of a douchebag that doesn't understand what he claims to support.