I cannot imagine this happening to anyone else if it were not about President Trump. Why do we do these things? To the people who do these things, do they seriously look in the mirror and say, "This is exactly what I would want done to me if I were doing what they were doing, except in support of my 'side'..."
From someone who has coached various sports for 16 years and refereed (retired) for 18 years, I can say this. The fans and parents are terrible... but AD's don't do anything. They don't want to lose the revenue, and they don't want the uncomfortable conversation/confrontation. So they let it slide.