There's currently about 600 lemmy instances, in many different countries, and those countries each have different laws regarding the protection of speech. Some of it is also just power-tripping mods or left-wing / right-wing censorship.

If this is happening to a community you like, you can always switch to the same community in a different instance. Eventually, the "official" community will have the most subscribers and the community with the censorship problems will wither and die.