If the topic blatantly promoted drug use, said it was cool and explained how to acquire illicit drugs, then there would be a problem. When a thread walks the line of being acceptable and unacceptable, it's at the discretion of the forum members. If anyone is offended or the thread gets out of hand, then action will be taken.
The same goes for any religious or political discussions. Good natured in creation, but can easily turn into arguments that offend forum members.
what makes it ok to have a smoking thread anyway, going by that quote i quoted you on
The thread I referred to was a general interest question, "How many of you smoke?" Naturally, marijuana was mentioned in that thread, in response to the original question.