There are dozes of anti trump subreddits which will ban you for not conforming. It's same with most if not all ideologically driven subreddits. They always have not pinned "go to r/<our-ideology>Debate if you are not conforming" type thing. To me every one of these echo chamber subreddits should be prevented from appearing on r/all (which is how people get exposed to these subreddits most often)