I don't think you understand my argument. I am talking precisely about discrimination against what you call "protected classes" (actually, I don't think the legislation is class oriented, but let's put that aside).

Companies are not allowed to do that, but individuals are allowed to discriminate even "protected classes". I can freely choose not to associate with black people, for instance. And that is a good thing. So even today there is a legal distinction between individuals and institutions.

And in a certain sense, "advocate of gun rights" is a protected class, because you have also non-discrimination (I would assume, like most civilized countries) on the basis of political opinion.