More liberal legal historicism... “they had laws like this... there are french laws like that... damn historical truth or if it was constitutionl or not”
And I am sure some cities still had slavery also back then etc...
The only way I could see it kind of making sense, is if that city got to be known as a mecca for duels. I can very well see even the most conservative sheriff then saying “Not here, gentlemen, this city is a no-duel zone.” But if that were the case, would our dear liberals tell us? Probably not.