A public place such as a restaurant is not an appropriate venue for politics. I was just trying to have a nice, relaxing dinner with my wife last night when the band played two songs insulting our current president Donald Trump. This is not a cheap restaurant and I expect more if I'm going to pay $20 per entree, such as a relaxing experience that does not make me feel uncomfortable. My wife and I were emotionally disturbed plus we are exhausted by the end of the week by what we already hear on the news channels. You have your right to do this but then put a sign out saying Democrats only tonight. I would have been more than happy to come back when that amazing guitarist who I listened to once on a Saturday. My point is I had no idea I was going to be forced to hear that because I assumed it fell under " you don't talk politics and religion with strangers" and most diners in a restaurant are strangers.
If the owner is reading this then I think you came to our table but I did not feel comfortable saying anything because everyone was enjoying themselves.
The food and waitress service was good but I really don't think I can chance coming to your restaurant again.