https://www.theverge.com/2020/11/1/21544501/facebook-rules-p...
https://www.businessinsider.com/facebook-mark-zuckerberg-thr...
In terms of groups and pages, The Intercept reported on this. And I've seen this directed at groups that were not explicitly antifa but were more socialist in nature. Some of the groups were targeted with a large number of user reports. I live in a red state. Some of the local groups & pages I followed were hit with many complaints from local conservatives. Which led to some of those groups disappearing.
https://theintercept.com/2020/08/20/facebook-bans-antifascis...
In terms of conservative popularity on Facebook, it looks to be partially organic. A mix of an older userbase and many conservative groups heavily targeting the platform. But the skew in the algorithms and the laxity regarding the rules also has a role to play.
The more reasonable (and widely accepted) reason as to why conservative content thrives on Facebook, is because conservative users are active in greater numbers on Facebook.