A Presidential candidate for a major party harrumphed that Kaepernick should go find a country he liked better. This is akin to suggesting that Rosa Parks should have tried the mass transit in Belgium or Bangladesh. That's the part about protesters that a lot of red-blooded Americans didn't get back in the '60s and don't get now: Those protesting are red-blooded Americans, too. They don't dislike this country. They disagree with something about this country. That's a difference, and not a small one.
It's often said that politics makes for strange bedfellows. Political protest can do that, too. Jim Harbaugh, who coached Kaepernick in San Francisco and works at Michigan now, said he didn't respect Kaepernick's "action." Meanwhile, John Harbaugh quoted Voltaire: "I disapprove of what you say, but I will defend to the death your right to say it." When two coaching brothers take different tacks, it's fair to say that Kaepernick splintered his audience.
And surely that was the point behind his sit-down: It stirred debate, and that's an American thing, too. We love arguing. And so we are.