Before they had a post 1933-rule, what's the story about 20 years now? I saw something about a politics after 1991 editing rule, but I never followed the discussion on those things. It seems like modern political articles got about 10 times worse than they ever were after these rules were implemented.
A long ways back there was a problem with random leftists editing 9/11 articles to claim any of the many conspiracies was the truth (same with the 2000 election, GMOs, vaccines (lol), and other cause célèbre) and the conservatives would quickly fix that shit. That was the original seed that led to the 1992+ topic bans. MONGO was a consistent enforcer of not-stupid-shit on the 9/11 pages so leftists who were convinced Bush planned it hated him and his 'cabal.' Check out this
talk page and search for MONGO; the dude was absolutely obsessed. MONGO was a sort of bogeyman for the actual leftists and there was an informal circling of the wagons for conservatives over time: 2006 had the 9/11 topic ban on conspiracies but it was very testy.
Later, the resurgence of leftist activism around 2008/2009 coincided with a drop in new admins, leading to a lot of existing admins and editors with lots of time, no job, and a newly energized leftist bent. Before 2008 there weren't that many people online whose entire existence was politics but then it exploded, particularly on the left. With the tea party movement a lot of the not-necessarily-leftist members shifted to the left and there was the first broad
American politics sanction. That originally covered all US related pages but later they felt it was overbroad and that led to the
American politics 2 sanction, 1932+. Together they led to a few prominent conservatives (like MONGO) from getting topic banned and was amended last year to 1992+. The reasoning was ostensibly to prevent conflicts over modern politics, but the Reagan-Bush years were definitely the start of the modern order, so I think it was more that people banned for being confrontational over Trump could still bitch about Reagan.
The gender gap/Gamergate crap also played a role because Jimmy Wales explicitly wanted to get rid of anybody opposed to the changes to what is essentially an unwritten "code of conduct," but I think it was already a virtually done deal at that point. Most of the major players opposed were older editors because newer ones were just banned outright or wouldn't even bother becoming editors. I wrote a little bit about that in the GorillaWarfare thread but I can't be arsed to find it now.