A sub moderator will establish it's own rules for what content gets posted to a sub. If no rules are established, then the global rules and the subpoal title are default.
Global rules apply to subs as well, then mods are free to add their own (related to the sub's topic). For example a food sub can limit posting to food related stuff only. If you post cars stuff and get your posts removed, this is not censorship. People are free to create their own sub to share and talk about what they like.
(post is archived)