I don't think the issue with .ml is that it's doing moderation according to a different viewpoint, it's that it is so unapologetic about deleting comments that don't line up with that viewpoint. Most servers have some kind of viewpoint, but if e.g. you or some other .ml person went onto any big server and started talking about Marxism or NATO or US imperialism or etc, I highly doubt that anyone would say "nope we don't allow that here" and ban you. But .ml does the reverse -- straight-up only allowing one side of the debate to exist. I had that experience, literally being disallowed from making certain arguments, which I something I usually only associate with /r/walkaway or other very extreme communities.
Everyone gathering around to yell at the person with the unpopular opinion is one thing; maintaining a mod enforced explicit one-viewpoint community where only one type of opinion is allowed to exist is very different, and very rare outside of the lemmy.ml / hexbear contingent or else places like Truth Social, and almost nowhere else.