The same scoffing could be directed at alcoholics, who often display anti-social behavior. The groups, whether SA or AA are moderated, and anyone who isn't their for support and help are kicked out. It's sad to do that, but until you recognized that you have a problem, you cannot be helped.
I'm just cynical about the whole AA and NA group therapy idea. My sister-in-law is a good-for-nothing junkie and all those groups do for her is give her a place to hang out with other junkies.
It just seems like a bad idea to put a bunch of people with the same addiction around each other.