The question still stands; step by step, how are you unapproving a post?
You should edit the post in question and click the "unapprove post" button, is this how you are unapproving posts?
If you edit the original post in a thread and select "unapprove post" it would unapprove the entire topic (as the OP is not approved then content shouldn't be displayed as responses to that post)
