@hrefna to me, your example (100 user server, bad/no moderation, 5 bad users, 95 good ones) is not a false positive (or a 95% FP) on a shared blocklist with the intent of "keeping out poorly moderated servers".
Those 95 good users are not false positives there. The server is the entity being listed, and it meets the criteria of the list.
A false positive is if the blocklist includes a server that does not meet its published listing criteria. (cont)