I'd argue that being forth right is a better approach. While they won't often ban on politics they do enforce a timeout when your comment gets down voted having a similar effect.

That's how the website works, that's not anything particular about the /r/politics mods.

Its actually a feature you can turn on and off as a moderator.

Are you talking about spam filter settings? Otherwise no, such a setting does not exist.

it's not just /r/the_donald that has that no criticism rule. I recently noticed that r/latestagecapitalism has that same rule. The number of subreddits where dissenting opinions are not allowed appears to be growing.

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)