If you don't belong to [insert religious group name], and you haven't been invited onto the Caucus thread by the original poster, you can't post to a [insert religious group name] Caucus thread, period. However, a [insert religious group name] Caucus thread must not discuss any other religious group, period. Doing so will result in the offending thread being pulled, and possibly [depending on the circumstances of the comment] the removal of the "Caucus" status, allowing non-[insert religious group name] members to freely post on the formerly-protected thread.
If non-Caucus members want to repost the [insert religious group name] Caucus thread material as an Open (i.e. non-caucused) Thread, they need to wait four hours, after which they may repost the material.
So apparently the official position of this site is you can comment on anything you like as long as you wait four hours.
Not on a Caucus thread.
I get the rule. It’s wrong.