It's simply inaccurate to say that the federal government "shut down" BP sex industry ads. BP took the action on its own because it's feeling some heat from the U.S. Congress and some state attorneys general.
btw, yesterday the U.S. Supreme Court refused to review a lower court decision which is in BP's favor. The lower court had refused to allow a claim against BP brought by three former prostitutes claiming BP aided their exploitation, citing federal laws which protect Internet free speech. See:
https://www.bostonglobe.com/metro/20...yPL/story.html