Well, if they fully mummified him, then it's a time-consuming process, but beyond that... most humans aren't great people, but they're usually not that twisted, darling. Things are a bit different for the rest of us. We aren't wired the same way.

[ Of course, Crowley's wires are incredibly crossed right now. His wiring is somewhere between human and not. ]

And it's not just demons. Angels aren't exactly the most sensitive of creatures, either. There are any number of creatures here who would have no compunctions about doing something like that. Angels, demons other than Meg and myself, vampires and werewolves and a bloody Leviathan.