I'm a Vietnam vet...and white as milk, and I understood "taking a knee" right from the get-go. 
All this pretense of patriotic outrage is about as shallow as anything I have ever witnessed in my beloved country.  I know, and the players who take a knee know, what all this feigned outrage masks...and  it's sickening and "sad".
I wish I could be on the field taking a knee with them.