I visit .ml and while I do occasionally get cross threaded with them they are, overall, not terrible. Yes some of the people associated with their instance can be over the top but by and large they are just people with a different viewpoint.
I tried to do the same with hexbear but ultimately couldn't, which may be my problem more than theirs.
How so? I'm having to go out of my way to find and engage with people who have alternate viewpoints & lifestyles because they tend to get pushed out of / banned from "regular" communities. That's the exact problem being discussed here.
In the broader context of the meme itself people start thinking they are in the majority because they are participating in online communities that have been carefully curated over time to silence anyone who disagrees.