In the aftermath of the attack on Charlie Hebdo, JJ Charleworth of ArtNet.com presents the source of the problem:
[Lois] Keidan (of London's Live Art Development Agency) concludes that today many people “feel entitled, not just to enter spaces and places where they do not necessarily belong, but also to demand censure and closure if they don't like what they find there."They go where they shouldn't be, look at things they shouldn't be looking at, and then complain that they aren't being catered to in a place that isn't intended to cater to them.
And that's all that needs to be said, in my mind. If you don't like what you see, stop looking at it. Instead, people feel the need to stop everyone from looking at something they alone (or a small selection of people) don't like.