I have NO illusion that there is any enforceable 1st Amendment right by players against owner for firing based personal speech expression.  Might be EEOC claims, or, depending on the circumstances, defamation claims, or contractual/CBA claims.  That could be true for either the sign above, or NFL players kneeling on the sidelines.

I think they probably COULD successfully fire for the kneeling.  

BUT, it is apparently the NFL OWNERS who are, in significant numbers, embracing the concept of Freedom of Speech as to what kneeling NFL palyers are doing.  

In fact, they are taking it beyond just the fundamental citizenship/resident right, and characterizing the kneeling as a virtuous, positive example of NFL player connection to community and efforts to do good.  

My discussion of Villanueva merely applied the warped, pretense-filled reasoning of Trumpist Yahoos who jumped on the little wave Trump created, and asked some what if's based on that warp.

But you knew that.