You can try https://www.hcaptcha.com as an alternative.
(btw, the GP mentions hcaptcha)
There's a limit to how much information one can get across that way, so we err on the side of explaining the spirit of the site and leave the 'case law' to specific moderation comments. One of these years I want to compile those into an extended FAQ or something, which could provide a home for the kind of documentation you're talking about.
If anyone is so weird as to want to read an entire 'essay' about this, I wrote one a couple days ago: https://news.ycombinator.com/item?id=27307680. The relevant subthread starts at https://news.ycombinator.com/item?id=27303886.