> parties. If you go to a government institution and tell them their boss sux, in theory you shouldn't be punished for that, and they'll keep serving you. But the same does not extend to a private bakery. Or a bar. Or any private property. Tell them their boss sux, and you might not get service

Except, of course, it's not that simple. There are a host of behaviors and traits that private businesses are not allowed to consider when choosing whether or not to provide you products or services. These carve-outs to free association exist because at any given time a large enough portion of the population exists of bigots who choose their associations based on characteristics that the rest of society has decided are not acceptable grounds for refusing service. So we compel service if we think not providing it is sufficiently shitty and harmful. Something similar happens when a private institution, or class of institution, is so critical to life or participation in society that exclusion serves as a form of semi-banishment. Such institutions are put under even stricter standards for association.

The idea that social credit or similar are totally fine and peachy so long as it's "only" private institutions using it is a fantasy entertained by rugged individualists who naively narrow their analysis of power dynamics to "big government bad" and discount their dependency on extremely powerful private organizations.