"Kaepernick began sitting during the national anthem this preseason. A silent protest to show support for people of color who are being oppressed in the United States, and to take a stand against police brutality. It’s an effort to use his voice and his position as a NFL player to effect change for the people who are suffering, and don’t have the same ability to create significant change.
"I am not going to stand up to show pride in a flag for a country that oppresses black people and people of color," Kaepernick said, via NFL.com. "To me, this is bigger than football and it would be selfish on my part to look the other way. There are bodies in the street and people getting paid leave and getting away with murder."
http://time.com/4973843/colin-kaepernick-national-anthem-nfl-kneeling/