This is just not true. They are very transparently trying to kick off users/communities that they don't "like".
For example basically any subreddit associated with the "alt right", except I believe /r/DebateTheAltRight or whatever it's called.
It's very simple:
(1) Identify community that you don't like, generally due to association with anti-leftist political views
(2) Find an instance of a threat of violence, regardless of context (i.e. the threat coming from someone who isn't a "real" community member)
(3) Use (2) to have a justified reason for "quarantining" the community, which is just the first step in a long, slow death-squeeze. From my understanding, those at /r/The_Donald saw the obvious writing on the wall and thus migrated to the donald.win quite some time ago.