The Donald was a hotbed of whackjobs, but it was also the biggest Trump forum online. They should be allowed to talk freely so the rest of us can laugh, rather than persuing the censorship route so advertisers don't leave.
I mean, those people won't follow a policy of wearing masks to save their own grandparents. Any site policy infringes on "mUh FReEdOmS".
They chose to be banned so that they could cry censorship.
It doesn't matter where "they" moved. What matters is what was published in that subreddit. They could just as easily have deleted the abhorrent racist posts and comments before they left. They didn't do that, so the subreddit continued to violate site policies.
Try this: create a subreddit, post child porn, and then never post again. What you'll find is that as soon as your post is reported/noticed, it will be deleted along with your account and your subreddit. It won't matter that you've moved on and now post your child porn elsewhere.
Racism and death threats have no place on Reddit as per the site policies that the mods agreed to so when the mods refused to comply, their sub was deleted. Nothing to do with politics.