BB, honestly, that is the part I don't understand. I know that given all that happened, the guy has a "baggage". But, let's focus on exactly what the guy did (at least as far as I know, there might be more to it than I am informed).
The guy decided to kneel during national anthems to protest police killings. That's all. That's all his "baggage". Even if you disagree with him, c'mon, it is not a big deal.
On one hand, I agree that a good deal of people interpret quite wrong -- or use it for their own political agendas -- the question of police violence against black people. But you can still protest the killings, you can still say "I want to live in a different world", no matter how you analyze the episodes and -- much more importantly -- the bigger picture.
Now comes the second point. I really do not understand why people say that taking a knee during the anthem is such an offense and/or a disrespect. The first time I saw it I actually thought "that's a smart way to protest". I really would like to know what is exactly offensive in taking a knee. I read some people say that the guy should protest by staying in the locker room -- which is one of the most idiotic things I ever read/heard. So, in order to protest you must disappear.... (in a few cases, it might work, when everyone expects to see you. In this one, where you are one among two hundred other players, it obviously doesn't ).
It is obvious that people doesn't want the guy to protest. No matter what he does, people will complain. If I was him, I would have changed my way to protest, just to prove this point. I would have invented some other kind of body language -- something like putting two hands on his heart, one for his country, the other for the victims, for example -- and publicize it properly. I am pretty sure that people would find a way to make it offensive.
Obviously, any protest will be always politically used. That's part of the deal. In a sane society, it should never be reason enough for silencing someone. I wonder where are all the freedom of speech defenders in this case.