Madame...check legal precendent. "Free" speech is not unlimited speech. There is slander, libel, incendiary speech, 'fighting' words. All sorts of limitations.
Granted, the remark made most likely did not present a 'clear and present' danger, but nevertheless was inappropriate, and as pointed out, the writer's condemnation of Geo II and the rest of them can easily be made in a manner not calling for violence.
Regardless of its legality, why it is so difficult to see that stating someone should be killed (shot, hanged) is wrong is beyond me, even if the person is the most hated man in America. If the writer had said someone should be shot or hanged because she or he was homosexual, or black, or asian, or fat, would it be a bit clearer as to how appropriate that remark would be in the context of a political discussion?
The posting has been reported, and the moderators will make the call.