Teams have every right to not hire a player if they feel their off-field activities would have a detrimental effect on the team. This happens every year in the draft. Some teams take a player entirely off their draft board because of off-field activities.

It is worth pointing out though, that there is no television video of Kaepernick not standing that I have seen during the national anthem. That is because the networks habitually (except for some national telecasts) do not broadcast the playing of the national anthem so they can get in another beer commercial. Is the habit of the networks cutting away from the national anthem to make more advertising dollars any more disrespectful than what Kaepernick did? Should the NFL insist that the networks broadcast the national anthem?