In addition what @OmegaStarScream have been mentioned above.

You can moderate self-moderated thread to delete other user post, but you shouldn't abuse it by using that's power if someone disagree with your thought. Constructive criticism post is considered as high quality post too and this forum has free speech. I don't know what's your purpose to create self-moderated thread, if you can't moderated a thread you can still report to moderator and let them decide.