Yeah, but Guro is typically snuff-like material.
It's killing people.
And brutally killing people, and you (and sometimes them) recieving pleasure from it, is creepy.
Diapers has a connotation with child enthusiasm, but my general experience in seeing those images, are that it's typically adults who are wearing them, even if they're pretending to be children.
To me that's less wanting to have love with children, and more wanting to be completely submissive or reliant on someone else.
And then there's the fact that it also ties in to scat, which is nasty in its own right.
I won't get my head around either one of them, in regards to liking them, but I think guro/gore is the creepiest for me.