If you liked this chaos, you'd love my 15+ years of cobbled-together efforts at limiting forum spam and the like. I suddenly don't feel quite so alone in the myriad efforts needed to tackle this sort of thing.
This happens all the time in cartoons that appeal to children but also contain subtle adult jokes so everyone can enjoy them on different levels.
What worked in the end was having any newly created thread send a message containing the post title & body to a slack channel specifically for monitoring the forums. Employees and our forum moderators were in there, and any bad threads were nearly instantly deleted. Eventually the spammers mostly gave up. Hard to beat a dozen human brains :)
Having a dozen reviewers, especially if spread across timezones, would be a dream!