“Lemmy” is actually not a platform like Reddit, it’s software and the network is decentralized (it uses the ActivityPub protocol) meaning each instance is operated by a different person (or group). There are also other similar softwares like Piefed and mBin that work pretty well with Lemmy. That is all to say that if an Admin or Mod is “getting fascisty” you can block that instance, join another, or even create your own. That’s the beauty of ActivityPub!