Because he has a history of very poor decisions regarding his public statements. For example, I think that someone supporting civil liberties shouldn't be wear

Because he has a history of very poor decisions regarding his public statements. For example, I think that someone supporting civil liberties shouldn't be wearing Fidel Castro T-shirts. His opposition to the Betsy Ross flag, and using his leverage with Nike to cancel a shoe themed with it, was asinine. There are actual, serious and thoughtful civil liberties activists in America, including those who are working to overcome the challenges faced by black Americans. They don't get nearly as much attention as Colin Kaepernick because they can't throw three touchdowns and rush for 100 yards in the same game.