Well, I don't know about that. Several big, big projects have no presence here at all; nor do countless little ones. Sometimes Bitcointalk comes up in search results and that's how ANN threads drive clicks, and I don't think people would keep paying bounties / advertising signatures if there was no profit in it (but who knows really... its a mystery).

I believe theymos would intervene in a thread if a project and/or account owners had clearly broken laws and been convicted of it. Up to that point, well, there's a few other ways in which threads can be locked or nuked (spamming, linking to malware)... probably more if you asked around.

Don't hold your breath waiting for scam threads to be locked in the meanwhile.