I would be interested in knowing what Chick-Fil-A does to prevent this. Pretty much every customer facing job that doesn't hope for charity at the end of the service is pretty bad in the US currently, but somehow they achieve the level of service of what I would get in Japan.

The only thing I've been able to surmise is that they probably pay the managers very well and mostly just hire smart high schoolers that may have been passed over or didn't know about internship opportunities, and pay slightly better rates than McDonald's. They still pull the same scummy things as McDonald's with pressuring employees for goals that only benefit the manager, but maybe its not so bad if you're getting paid more than your very young peers.

Chick-Fil-A would probably try to attribute some religious meaning to the Sunday off for their adult workers, but it seems like any company could just guarantee a day off on the weekend for their workers.

Tribalism, presumably. Chik-Fil-A has intentionally made their brand about serving a specific tribe, being part of that specific tribe. That tribe has ideals and to work for that tribe is to live up to those ideals and if you don't live up to those ideals you are fired and probably not a "real" member of that tribe. It's tautological, but so is a lot of tribalism.

Given how much of that tribalism is also explicitly religiously coded, I find it's hard not to want to apply harsher words like "cult-like" to Chik-Fil-A, specifically, but "sect-like" is probably more accurate given how predominant both their business culture tribe and religious tribe are in American politics today even if "sect-like" doesn't have quite the same harsh connotations designed to help you question the systems of power in place.