Tolerance is fundamental to freedom. If we stop tolerating actions or opinions that we disagree with, you stop freedom, democracy disappears and is replaced by dictatorship. The irony is for the idea that kneeling during the national anthem is disrespectful and should not be tolerated, we are giving up the very freedom that too many gave their lives for.
You can not dictate respect. Dictating respect is counter to tolerance and is counterproductive because respect is earned, not given.
Do you really want freedom? If you do, it starts by tolerating those with whom you disagree and not treating them with contempt.