I'll back up Currawong here.
First, not everyone who gets banned is a scammer. There are other reasons, too.
Second, these decisions are made privately. It was decided a long time ago not to air dirty laundry and hold people out for public humiliation. When people go over the edge, we clean it up and deal with it in private.
It isn't fun to ban people. We'd rather not have to do it. And it isn't done over minor things. You'll have to take my word for it, but some have been a few miles over the line.
Hypothetically (and I haven't seen this happen and am in no way referring to any member past or present), what if someone posted an obscenity-laced racist rant? Obviously, the post and all responses would have to go. The member would likely get a temporary ban and a stern warning.
Then they come back and do the same thing again.
In that case, the member has to go. They were well over the line, ignored a previous warning and ban, and continued with awful behavior that would derail any and all discussion if allowed to persist.
I'm not going to talk about anyone in particular, but some pretty ugly stuff shows up now and then. I wish people were level-headed and thought through the consequences of posting these sorts of things.