Yeah. this is the weakness of Mastodon. Every server has it’s own rules but if the owner does not like what you think, they will ban you. It is always better to take backups at least your followers even you can not drag your posts to the new server. And that new server must be run by you if you do not want to face any censorship. In that case, there is possibility that other instances can ban your server any time. I hope it evolves to a real decentralized network in near future like nostr.