Just unsub from lemmy.ml and lemmygrad.ml communities. You might still see them in All if your instance federated with them.

There's some overlap between open source enthusiasts and anarchists/communists. It comes with the territory. Most of them are not tankies, but rather are anti-patent or anti-IP or similar, but there's definitely a few on the fringe. And open source folks are among the earliest adopters of federated networks so a left slant is expected, to a limited extent.

So far I like it here. I'm a centrist (by Canadian standards). Ive seen a few extremists leaning tankie if alt-right in various threads, but that's okay. The centre seems to be holding and voting them down.