First, I need to say that generally these are not “subjective.”
“Being a jerk” is our generalized term for misbehavior. It’s short and to the point, and avoids the 8 volumes of legal and technical refinement. Basically, we expect posters to be reasonably polite to other posters, and for discussions to be held in an atmosphere of sharing and learning. (The only exception is the forum called The Pit.) Violation of the basic rules – such as leveling personal insults at other posters – results in scoldings (Mod Notes) or Official Warnings.
Since we’re all fallible (except Cecil Himself), we tolerate a certain number of scoldings and Official Warnings. After that, we get to suspension or banning. How many? It depends on the nature and severity. We’ve got a lower threshhold for (say) racist remarks directed at other posters, than we do for mild humorously pointed barbs. We also watch for repeat offenses: we expect people to learn from their prior mistakes, and not to repeat. So, if you have two or three warnings for the same offense over, say, two or three years, not to worry. If you have two or three warnings for the same offense over, say, two or three weeks… well, you probably aren’t a good fit for these Message Boards.