Polyamory

I'm just wondering why I need mod approval for a post? I started a thread and didn't need mod approval (it instantly posted) some one replied, then i replied to that, also with no mod approval, then a different person posted in my thread, and i replied to that only this time the reply i tried to post didn't post instead I got a message saying "Thank you for posting! Your post will not be visible until a moderator has approved it for posting......etc, etc"

I must admit i did not read the forum rules but i have been to several forums for several different topics and for the most part they all have the same rules. I didn't use any profanity or talk about anything illegal or any other obvious reason.

Also it would be more logical if every post had to be moderated not just some random one. Especially considering it was me posting in the thread i created

EDIT: and minutes later this thread i just created also just posted without the need for mod approval