actually a few years ago there were definite concerns with their bookkeeping/accounting practices, which made it actually impossible for me to feel comfortable giving them money. but that has changed and also, the current landscape of fandom makes it imperative that ao3 stay up. https://twitter.com/PlagueSquid/status/1183365291889303553
one thing to also note is that when you donate to otw, you are donating to more than just ao3. yes, ao3 is the massive chunk of it (see graph below from the official otw 2019 budget), but otw also funds fanlore and the journal of transformative works
for anyone who has interest in ancient fandom drama or where certain fic terms come from, fanlore is an invaluable resource, esp. with the difficulties in navigating fandom wank's archives. and i have wasted a good afternoon or five with the journal!
i know none of you following me have an issue with ao3 "harboring" "nasty" "problematic" fics, so instead i'll pivot and say, ao3 is now where lots of chinese-language fic writers post their stuff, with how fraught danmei/bl content is in china. that's incredibly important to me.
TL;DR i used to be a conscientious objector to donating to the otw. i am no longer one, and i hope that if you have a few dollars, you consider donating