Shouldn’t there be some connection between the target of the vandalism and the goal of the protest? If you are going to inconvenience people it’s supposed to be so they are led to think hard about your issues, not so they are scratching their heads about your intentions.
What does "nah" mean? That they didn't have to replace the books, or that "other libraries were destroyed so it's okay to vandalize this one" isn't a tu quoque fallacy?