You di not have to be a manager to refuse services, especially if you are the only employee on duty, which he was.
Please quote where I mentioned at all that the man taking the video was in the writing g for his political beliefs? I never once said he deserved to be refused.
Bottom line is that once you are refused, rather it's a good reason or not, you are trespassing. That's the law, it was linked above. Private businesses are protected in every state in this way.
At that point he couldn't make a purchase, so why would he stay? The only reason he did was to record and further the argument, that is the part that is harassment. It has nothing at all to do with his political stance.