Literally every gay man I know is concerned about HIV. Lots of people go on prep. There is not a subculture of people spreading HIV consensually or forcefully. I have never met a single person in either online communities or real life who would advocate for that practice.

I have quite literally been to sex dungeons. I have seen people set fire to genitals (in a safe and controlled way). I have seen people participate in far more extreme practices. I have never seen anyone advocate, fantasize, or talk about any of the things you have mentioned.