If this is another Just Stop Oil one, then they more or less clear the stunt with museums beforehand. At least in the article I read about the soup or whatever, they had checked to make sure that the painting wouldn't be harmed
politics is a performance. leon czolgosz said "I killed the President because he was the enemy of the good people -- the good working people. I am not sorry for my crime. I am sorry I could not see my father." And they gave him an Oscar.
Politics is a performance in general, but there's transformative performance and meaningless. Isolated adventurism in general goes nowhere even if you pull a Czolgosz. Doing something like that might give organisers more of a propaganda win but it won't do the work of organising. Building momentum around movements and ultimately parties is what gives the goal enough weight to resist reaction.