Their reasoning was that this was a form of governmental control over working and the freedom of workers, just like slavery was.
Every time they defeated a minimum wage law, or broke a union, they congratulated themselves for standing up for “freedom”.
Anyway, this is one of the reasons that the Republican party drifted into conservatism slowly after the Civil War.
We are seeing something similar now, with Democrats so focused on the rights of smaller and smaller groups, it’s starting to look like “extreme individual rights” all over again. Will they drift towards conservatism while Republicans do the opposite, cross-pollinating some positions between them on the way?