Sometimes the country needs a wake up call.
There are so many in this country who (a) think there is no more racial equality problem, (b) doesn't care that there is a racial equality problem, or © is glad there is a racial equality problem because it benefits them personally.
To me, the flag/anthem represents exactly what you say - the idealism of freedom, liberty and equality and to honor those who stood for them (especially but not excluded to the military). That's why I will always stand.
But that flag/anthem doesn't mean the same to everyone. And even if it does, it doesn't prevent one from making a statement in this way when they find it necessary.
Why would the "average white guy in the stands" feel "mad and disrespected" by the black players who are exercising their first amendment right? If they're mad then that's on them.