The Zot line that is crossed usually is repeated Trutherism, racism, threats, vulgar language, or promoting liberal causes or candidates. Not just for the sake of liking a certain person (unless they are trying to use the site to advertise for overt Liberals of course).
In the case of the Zot! on this thread, this was a long time coming for a truther who was warned many times, even by Jim himself.
Seems like Captain Kirk needed to get a "Buy a clue" button from the local pawn shop. He / she / it was one those "Nope, those planes never hit the Twin Towers", even though the horror was captured on file.