No. This is equivalent to what happened in the 1950s about restaurants refusing to serve blacks.
Its a free spedch issue and these People need to be SUED under the Civil Rights act.
If you serve the public, that should include ALL the public.
Were the situation reversed, the ACLU would fo this gratis.
I’m not a lawyer. And I don’t play one on TV. But you can file a civil rights lawsuit for a “protected class” reason only (race, national origin etc.). Political affiliation is not one of the protected classes.
And it’s not a free-speech issue. You can’t just say whatever you want on someone else’s property.
But as you said, if the situation ere reversed the ACLU would sue. The lawsuit would fail. But they would try anyway. And maybe Antifa would show up, and break a few windows.