When the Founding Fathers wrote the Constitution of the United States, dueling was dueling was an accepted and honourable fact of life, in fact, three of our Founding Fathers met their deaths in duels.
Insults, mockery, verbal abuse -- all and more were accepted grounds for an issuance of an invitation to a morning round of "Pistols for two; coffee for one".
When the First Amendment Freedom of Speech was added to the Constitution, it was as the first of the Bill of Rights -- controls upon the government. The government would not be allowed to abridge the right of free men to speak their minds.
At the time it was abundantly clear that -- through the mechanism of dueling -- society would provide a check upon the abuses of Freedom of Speech by way of dueling.
In simpler language, if a citizen were to use their guaranteed right to Freedom of Speech to insult, abuse, denigrate, mock, harass or distress another -- then sooner or later that citizen was going to get the stupid beaten out of him with a cane, bleed out on a Vidalia sandbar from multiple knife wounds, wind up skewered on the end of a sword, or simply have a large percentage of their vital bits blown out through their spines by way of a heavy-calibre pistol ball.
In the America of the Founding Fathers you were polite and courteous, or you got your butt killed in a duel.
Which worked remarkably well, up until we decided that we was civilized and did away with the barbarity of the duel.
Probably not a bad idea -- except that we never came up with a replacement for the check on incivility that the duel gave society as a whole. We left the right to speak your mind, but we took away any deterrent to being a jackass about it.