The main devs are MLs, but I don't think that necessarily makes them tankies. The Lemmygrad instance is the worst offender if that bothers you. This instance is not sectarian, though it does have a leftist culture in general.

There is an anarchist community already on this instance as well, and it's likely this instance trends toward progressive politics as users come in and push the culture toward the mainstream.

Keep in mind, the technology behind this platform is mostly agnostic. Anyone can build an instance that facilitates their chosen beliefs and choose to only federate with other like-minded instances.