It's more the fact that the people who like this sort of thing have a kind of elitism about them, as if liking some obscure 70s art piece makes them better than people who like K-On or something. It just really pisses me off.
Liking/disliking a style of artwork is entirely subjective, but I personally think Belladonna is filled with ravishingly beautiful imagery that I'd happily have framed up on my wall. Exhibit A...
There's plenty of 'uglier', more disturbing imagery due to the subject matter as well but even that is very impressively drawn.