It is against the UN human rights of freedom of expression. Which states and I quote: "Everyone has the right to freedom of opinion and freedom of expression". If you get offended by a piece of art just don't go and see it of buy it it is that simple.
The world is what created the feel for the need for censorship and censoring artwork. Over the years people have slowly sexualised the human body to the point that it's gotten really crazy. People obviously pass on a lot of their opinions to their children which is why art has continued to be censored over the years