Because it's a fun industry that typically doesn't exploit real life people, personally I enjoy making them just because peeps seem to like something I'm ok at which is nice.
I'm actually a gay-demisexual(little to no libido) so i don't typically care about porn in general but i like making something peeps find neat.
Plus some of the nsfw games have had some of the sweetest moments, few and rare sure but also very heart warming. Extracurricular Activities had me crying and in suspense, Socially Awkward is just sweet goobers with a little sexy thrown in. And Kingsguard literally had me on the floor crying over a socially neglected fox ninja and weirdly wholesome lion.
It's not all just for the sexy, sometimes it just the deep simulated connection that super appealing, :3