Excellent. In accordance with your beliefs, let's edit your comment to replace theDonald with some subreddit that I dislike. I'm sure this is totally fine, because after all I'm confident that they're "horrible". We won't need to mark your comment as edited. This is, of course, "OK".

Editing comments to make it seem like people are saying things they didn't is basically never OK, no matter where the post was made.

s/basically//g, it might also expose them to liability. safe harbor is already in question for sites that are moderated. I imagine editing user content crosses another legal line.