Perhaps you are explicitly arguing that the legal framework of public accommodations should be extended to content hosting but you need to make that argument explicitly with full understanding of that framework and not by casually dropping that legal term into the discussion.
Going after 'identifiable groups of people' is phrased to sound terrible but doesn't seem to be what is happening. The policy changes are about content not content creators. Not arguing for or against the policies just pointing out that they aren't targeting content creators in a illegal discriminatory manner.
You may have a point about the rules changing but that is basic contract law. Nothing new there and in any case there needs to be a mechanism by which the hosting terms can evolve, they aren't immutable.
So it's one thing to ban someone from some public accommodation for specific behavior and another thing entirely if you don't serve that kind of people or if you play games with the rules and enact a grandfather clause that somehow only applies to 'that' sort, but avoids spelling it out.