I and most other Gay men find all that extremely severe bizzare and rare... whatever floats their boats, but, sheesh pretty grotesque stuff practiced by only a tiny tiny minority... the fact that it is in a disproportionate amount of porn attests merely to (a) desire to attract attention and sales by these sort of severe behaviours that some people enjoy viewing only voyeuristically , and (b) the sort of extreme personalities and lifestyles of those who groom themselves deliberately for a life of producing and staring in porn... again a very very very tiny minority of the gay community.
99.9% find bareback and fisting really gross, dangerous and horrifically bizarre. Anytime I've ever been watching a porno and there's an unexpected fisting scene, instant hard on killer... I think you would HAVE to be wigged out on a depersonalizing anesthetic like K to the point where you feel your body is some kind of foreign alien object to get into that... then again I've seen some utterly bizarro stuff in straight vids (by accident) as well, so I think its all about something that will cause your product to stand out in a crowd of millions of identical vanilla sex movies.
And I agree with you about sex on K... WTF??? First time I ever tried it someone offered it as an enhancer on the dance floor creating sort of a trippy swirl of an experience... but once I tried masturbating while on a buzz of K and it just seemed like the most uninteresting thing possible... a total libido-killer IMO.
I know lots of bisexual and gay men who are not into vanilla sex and some do enjoy fisting even if they don't use drugs and do practice safer sex so maybe that's it? IME fisting is way more common than people want to admit or talk about. Lots of men have tried it once or a few times on the giving or receiving end and it's not something they do all the time when they have sex, or they might have tried it and discovered that it is not for them.
Heh I find fisting in porn both with men and women to be HOT but I don't want to see a rosebud, prolapse, or blossom.

Some of my friends who are into fisting find them hot for some reason. I have a friend that's an anal sex top and he only did fisting once but that was because the guy he was dating/in a relationship with wanted it done and he said how it was hot when his hole gaped and my friend cut/trimmed and filed his nails, used gloves and lube and just put only his hand in not his whole arm like some are into, so I could see how it's hot when done to someone.
It's odd I can do all sorts of sex involving power exchange/BDSM to men and women but I find rimming/being rimmed to be NASTY.
I have no idea how many bisexual and gay men PNP or do what I wrote about. The OP asked about using K during sex and I've met gay and bisexual men online who are into it.
I can see how bareback sex with one partner who you're completely monogamous with him/her is hot but I've never done that with any men or women since I have a hard time trusting people sexually since I've had people lie in the past to me.
Like you wrote I do know lots of bisexual and gay men who watch bareback porn just on DVD or on Xtube or fantasize about it but they don't actually have it.
I'm friends with gay and bisexual men who've been having sex with men for over 20 years and they've never done bareback sex with anyone since it's dangerous.
But pretty much everyone I know except for myself and the bisexual and gay men I described above has barebacked.
Some will do it with the current boyfriend or whatever guy of the moment they're dating after just 1 test where they think this means that the person is really neg but I'm sure you know just why that's not always true, their friends that they sleep with, and sometimes in the heat of the moment with tricks.
Anyway if you want we can talk about this off site or in another thread?