I just checked. There have been about 120 banned. All but 2 or 3 have been for posting spam or porn. (and, the most of these were obviously spambots.)
Those remaining 2 or 3 were banned because they started spewing obscenities, or otherwise refused to accept our rules. Typically, when we (the mods) explained that their behavior wasn't acceptable. They couldn't seem to accept that there ARE reasonable guidelines to follow.
Generally, it's NOT about what you say, although we do have limits. It's more about how you say it. If you stay civil, no problem.