Okay, so I think it is very tied to the fact that there is not a lot of fics about established Poe/Finn. The movie gives us a golden opportunity to write slow burn or falling in love fics. Rey going off on her own to train with Luke for an undetermined amount of time, leaving Poe and Finn on D'Qar.
That's what drew writers on the first place. That, plus the ship introducing a lot of people to the concept of fandom (it got me personally to start writing) and maybe younger fans than with Kylux, it isn't a fertile ground for kinky stuff.

Personally, I'd love to read and write kinky stuff, but really only if they're in an established relationship, and to get the feeling right, I always feel like I need to write more. My brain refuses to compute when I read prompts about the First Order being open about sex or making sex part of its culture. I'm like, cool headcanon, but not mine. I can't see Finn as opening about his kinks to Poe until time has passed. Same for Poe, can't see him as the guy to try and say anything that might make Finn uncomfortable.

I think fandom will come around, eventually. Kinky sex can be hot for these two if it's very consensual, because it shows off how much these two love and trust each other.