@Saket All the pearl-clutching I've seen has centered around the extremely superficial idea of 'destruction' and how that is 'not an acceptable way to protest', sometimes invoking slippery slope arguments like "but what if next time they do it to an unprotected painting".

Upon further inquiry when people argue this, it then turns out that the only 'acceptable way to protest' to them is something that produces zero inconvenience and has zero risk. Seems to be nothing more to it than that, just the same old tired argument where the only acceptable forms of protest are ineffective ones.