Forum content is held to the same standards as anything else on the platform.
What gets removed: harassment, hate, sexual content involving minors (which is also reported), spam, and posting other people's private information.
What does not: disagreeing with staff, criticising the product, or posting a film somebody dislikes.
A hidden post remains visible to its author, with the reason. Silently disappearing someone's writing teaches them nothing and reads as a bug.
Locking a thread stops new replies but keeps it readable — most locked threads are locked because they are resolved and drifting, not because they are bad.
Moderation actions on the forum use the same audit log as everything else.