I write romance fic in Hellsing and Silent Hill. I'd call those horror fandoms, but I get the feeling that's not what you're referring to.

Anyway, I get enough unrelenting horror in the canon, sometimes I want to write about what happened to the people who survived (or if they would have survived.)

I include horror elements, when I feel like it, but... that's it.

(I'm not sure what you're hoping to accomplish by complaining in reviews. If people want to write fic you don't like they're probably not going to change their minds because you reviewed.)