Doesn't the fact that finding instances of violent rhetoric among alt-right posters, regardless of context, sorta make the case that maybe this is an endemic problem and not a purely political suppression?

There are a lot of really hateful people among that group, in ways that just aren't true for other politically aligned communities.

I mean, the Dirtbag Left folks have their assholes too (note that the Chapo sub was banned too), but they're comparatively rare, notable in isolation, generally have names associated with them, and (really importantly) tend to be shamed and controlled from within their own communities.

The alt right is a bunch of assholes, plus a bunch of people who make a habit of tolerating assholes. That's a toxic combination if you're Reddit.