You are correct that they can ban.....but not for race, color or religion.
As for banning for political affiliation, I don’t think that horse has been buried. I suspect that there will eventually be court cases resolving that question.
Jones might be obnoxious but the fact is that is not why he is banned because there are persons more obnoxious who have not been banned.
This isn’t race color or religion. Jones is obnoxious, they are media companies, they are judged by the message on their medium, they didn’t want his message on their medium.