At the bottom of each post is a blue button labelled "Report". That's the "report post" button. If you click it, it will give you a popup and you can report something wrong with somebody's post, including your own. If you want a thread moved offline, then report the first post in the thread.
BF runs on a database. So, nothing actually gets deleted. Databases do not deal well with deletions. We move things offline where the regular membership cannot see them.