Kap's protest is well within the meaning of the First Amendment:
Freedom of Expression and "the right of the people to peaceably assemble and to petition the government for a redress of their grievance", was in effect when members of the community of the NFL brought attention to the world of the wrongful murders of African Americans.
I think the Players Association is going to reject the league's rule and will tell players to continue to kneel if they want to express their first amendment rights. Which I agree with. The rights are there written in the Constitution not for show, but to give the people the teeth to stand against even hurricane force winds against them.
And the reason they are kneeling is still being clearly played out across the country as evidenced in continued videos showing black men being beaten and murdered for no other reason than being black. It has to stop.
I think the players are overplaying their hand
What does it take to get the kneeling to stop?
Cops will kill unarmed people whether they kneel or not. Time to move on
I see it less of overplaying their hand, and more of the message is not being taken in the way they thought or hoped it would. It didn't get people to think about issues with policing, it made people talk about the overt act of kneeling or sitting or whatever during the anthem.
The protesters who want to keep up with this are unable or unwilling to realize what they WANT the message to be is not what a large segment of population perceives the message as presented. Now we are at the point of arguing about the messenger (the act) instead of the message (why they are doing it)
Also Kaepernick getting photographed with those "cops as pigs" socks didn't help his case.