The idea that something is art Art has been used to defend many acts thought to be immoral.
No one cares. It's not as if they are creating charged work that fundamentally changes the way we look at the world - shifting out paradigm from a Malthusian dream to a sustainable future, say, or making us more sensitive to the Other.
Indeed the idea that art need not be moral is another way of making art ABOUT morality in some sense - the negative one.