Two points in rebuttal, Jim:
1) The troll isn't contributing, just causing trouble.
Same as walking up to people on the street & shouting at them, or following them around & contradicting everything they say, or saying things in person just to start a fight.
2) This is not a gov't forum, so technically we don't have rights here.
Not that either Mike or John is likely to actually restrict us much in what we talk about, but they could go well beyond the rules in place now.
If they chose to ban the troll, as well as any other accounts from that IP address (or however they figure that), they could, for any reason or no reason other than "we want to".