1000% - as a private citizen he has a right to free speech.
The reason I can't stand Colin Kaepernick, in addition to not agreeing with his message, is that as an employee of the NFL he does not have the right to express his message during an NFL event.
Maybe it should be different for public employees though - thinking this through - "Congress (the government) shall make no law ... abridging the freedom of speech" - in this case his employer is the government - maybe they should they held to the same standard here? Maybe it's different for public employees? I don't know, IANAL.
My wife made a great point - he was merely saying in his video that as a police officer he swore to uphold his code of ethics, the Constitution, the core principles our country was founded on. How can you be punished in any respect for that? Again, I did not say I agree that he should be punished. It was just speculation that things may (or may not) have gone differently. Just some points to ponder and discuss.