it's just that our society is so very fucked up right now. This is not a thing that anyone should spend any time either getting upset about or defending. But that's not what is going to happen. If they are offended, It would be great if a group of concerned citizens would reach out to the Chiefs organization and explicitly ask them to not allow people to wear traditional costumes or whatever in the stadium. That would solve the problem at the antecedent stage. If the Chiefs organization refuses, then they can make a case in public. But people are always going to do stupid horsefeathers, not out of malice all the time, but out of ignorance.
There are obvious counterexamples. A bar owner in my old home town posted on Facebook his food menu and a White Power hand gesture, within 8 months the bar was on the verge of bankruptcy and sold.