The more-distant past was (relatively) dirt poor. Libraries tended to be (or be in) major buildings, that were obviously associated with the wealthy. So - it'

The more-distant past was (relatively) dirt poor. Libraries tended to be (or be in) major buildings, that were obviously associated with the wealthy. So - it's like asking why Willie Sutton robbed banks. (Plus - if you were a violent, drunken barbarian, already having the time of your life raping & looting - then what could possibly make things even better? Yes! - a giant fire!!) Or - any time you've got a nasty cultural conflict, and libraries are near-and-dear to just one side - yes, obviously the other side will go after 'em. Ask an old Playground Monitor whether verbal bullies shuffle through various subjects & words, searching for whatever will get the worst emotional reaction from their victim. (However much it mashes some people's buttons, I suspect that going after libraries for very calculated, 1984-ish reasons is relatively rare. If your side has effective control of the police and media, then maybe 0.01% of the population really cares that some dusty old book proves your current propaganda to be a lie.)