Sure can happen again, if it happens again it can be dealt with the same way it was dealt with last time: vote the bastards out and maneuver around Hollywood to make the movies.

We have a very narrow carve out of service obligation that constrains businesses from refusing service for intrinsic properties. Apart from that, at the federal level: no, we don't and shouldn't obligate businesses to serve Communists. We don't obligate them to serve Nazis. We don't obligate them to serve the KKK. We don't obligate them to serve Democrats. A business that's too picky about the color of people's money is a business that leaves money on the table, and that is almost always counterweight enough.