The flip side of your argument is that only after the trade in slaves was restricted to domestics, did the southern slave owners decide that it was a practice worth fighting for.
Actually, the Northwest Ordinance, restricting slavery in the new states was passed during the time of the Articles of Confederation. To me that suggests that all agreed that slavery was a practice that should be limited, reduced, and cut back. It would have been rather nice if the practice could have been limited (as the Republicans wanted, by restricting slaves in the Territories) until the pro slavery forces were weak enough that it could be abolished. The pro slavery forces didn't want that approach. And the war came.
despite the FACT that roosters crow before dawn, the sunrise is NOT caused by chickens crowing. one event simply follows the other.
the WBTS was NOT caused by slavery,or the slavers fervent desire to protect the "peculiar institution"!
150 years of hypocritical, KNOWING,arrogant, SELF-righteous, LIES from the lunatic fringe of "DAMNyankeedom" does NOT make their case any less PHONY, despite how LOUD they scream their KNOWING nonsense.
free dixie,sw