Kaepernick: 'I don't see what's un-American about fighting for liberty'

San Francisco 49ers quarterback Colin Kaepernick remains undeterred by critics of his protest against police brutality and racial inequality in the United States.

Kaepernick was booed prior to his start Sunday against the Buffalo Bills, and continued to kneel during the national anthem. Fans in Buffalo even broke into a "USA" chant, much to Kaepernick's confusion.

"I don’t understand what’s un-American about fighting for liberty and justice for everybody; for the equality that everybody says it stands for. Now, to me, I see it as very patriotic and American to uphold the United States to the standards it says it lives by. That's something that needs to be addressed," Kaepernick told reporters postgame.

A fan reportedly threw a beer bottle at Kaepernick during the game and was ejected. Kaepernick, however, was unaware of the incident.

"If they did, they had really bad aim."