You are more than welcome to block any and all content from that instance. You can do this by going under your user settings and clicking on the “Blocks” tab and searching for lemmy.ml in the Block Instance section. That’s the thing about Federated content. You have the power to selectively engage with the content of your choosing. You don’t get to quarantine others because there is no centralized authority that gets to say “your instance gets stuck in an internet ghetto where it isn’t allowed to interact with other users.” You have to quarantine yourself by excluding content. If that doesn’t work for you, then maybe it’s less that you dislike their authoritarian ideology and more that it isn’t the same flavor as your own.