Just an added note here. The person that owned the gallery and got punched in the face was a woman.
In my opinion, whatever you think of the "art", the act of punching a woman in the face is pretty brutal. I saw her face and it wasn't a slap. It takes a special person to walk in and punch a woman in the face.
I think protesting the "art" is appropriate is you feel the need, but physical violence to the person is criminal.