“What if you got smacked because you didn’t stand for the so called black national anthem, or because you didn’t vocally support abortion?”
While you make some valid points, the above statement weakens your argument. Equating those actions with standing for the national anthem is ridiculous in my opinion,
The point is exactly the same regardless of the unpopular expression. Just because something means something to many people doesn’t mean everyone has to agree with it. It certainly is not a cause for violence.