I believe that all artwork has a place, even disturbing art. However, it depends on the context. If you have a painting that is hideously scary and you have small children in the home, it is not responsible to hang that painting. If the painting brings your own mood down, it probably shouldn't be hung, but stored away in your portfolio.
Art galleries should be able to hang disturbing artwork, but should have a warning note posted outside of the entrance to warn people of the adult content just as there would be warning on a TV show. I went to an art show where half of the paintings were of a gross disturbing nature. I left sick, wondering what frame of mind could have driven people to paint what I saw. But I'm a big girl, so I got over it. I'm just glad I hadn't taken a small child with me as there were no warnings posted outside of the entrance.
I still am of the belief that all artwork is art because it is a creative expression. Just because it disturbs others does not make it any less a piece of art. It definitely has it's place though.