Yes, of course. I agree with that. There is a line that shouldn’t be crossed. But that line is nowhere near “tamer” extreme fetishes like feet or whatnot. That’s what I meant to express.
Safe, Sane and Consensual is a pretty good “rule” in that regard. Necrophilia, Snuff, Rape, etc for example are neither safe, sane nor consensual.
If something like that is your fetish and you get off to that on a purely fictional and fantasy level, though, then I also don’t really see THAT much wrong with it. As long as it, like you say, will never be practiced in real life.