I said this before when JSO used "washable" paint on Stonehenge: they are punching in the wrong direction. Billionaires don't care about human life, so why would they care about a painting?
These works belong to humanity, and by defacing them, you aren't winning converts—you're just pissing people off. Go vandalize something that belongs to the billionaires making things worse for the rest of us; unless you can win people to your cause, you're going to remain small-time vandals that get outsized prison sentences and unflattering media coverage.