Eh, I tend to chalk it up to "Has a dark imagination and/or some truly weird kinks" and not worry about it unless it's accompanied by non-fic weirdness indicating it really is part of a bigger problem. Like there's been one or two people out there who get into discussions about incest-fic with "It's good and healthy and natural! And so is actual incest that people do in real life! We should all screw our relatives!" statements, and I'd be a lot more 0_o about incest-fic written by them, or fic that turned into a "Why this is good and right lecture!" written by anyone, but usually I don't read much into it.

Of course I've got kind of a weird imagination myself sometimes, and I don't want someone to go "She really got into having the main character tormented in that fic/she wrote rapefic/she combined sex and broken glass! (Thank you, Riona.) What's wrong with her?" So I skew strongly towards not judging others for that sort of thing.