We were inciting violence against long dead historical figures. That's the official reason. In reality reddit has consistently b& subreddits which turn a critical lens on the rest of the site.

The earliest one I can remember being a part of was the r/shitredditsays community which helped expose a bunch of child porn adjacent and other gross communities and misanthropic power users. Nothing was done about these communities until the efforts of r/SRS to shed light on them were picked up by more mainstream media platforms. This resulted in the questionable communities being banned (they mostly just popped back up under different names) and also the r/SRS subreddit network being banned.

Reddit will tolerate circlejerk and drama communities, but once people actually take intra-site activism seriously they shut that shit down ASAP every time because advertisers tend to recoil in horror once they learn what the platform actually hosts.

The dynamics are a bit different these days now that platforms are being co-opted by well funded political parties and their subsidiary support orgs.