Free Speech.

As a longtime First Amendment scholar, let me just go on the record saying I am perfectly ok with the President of the United States calling activist athletes "sons of bitches".  He is simply expressing his beliefs.  If you support the athletes disrespecting the national anthem and our country* by making a pre-game scene, then surely you have to respect when other people also express their beliefs by answering back?
-------------------------

* This goes to the heart of the problem with the kneeling-during-the-anthem protest.  What exactly are these boys protesting against?  Police brutality against all people?  Police brutality against black people?  Wars?  Soldiers?  The flag?  The South and the Confederacy?  The lack of reparations, and the imposition of jail sentences on convicted criminals?

I understand the symbolism, but this is the problem with having under-educated men, who are paid to remain boys playing games, serving as the face of your "movement":  the message gets muddled.  It's laudable to want to create Change in society by addressing injustice.   It's much harder to achieve than dissing the national anthem, or shutting down freeways during rush hour...

First:  figure out your message.  Remember: don't be exclusive;  be inclusive.  If you want to create Change, you need allies, not more enemies.   And not everyone will bow to you.  "King James" doesn't understand that.  "Steff" Curry is learning that a White House invite is a privilege, not an expectation or reward for winning a game championship.   Good.

(Just because you can bounce a ball or toss a pigskin does not mean you qualify as a respected national leader or thinker.  Know your role...)
 --------------------------------
ADDED:  To top the sitting-during-the-song trick, some have suggested flag burning. I think the "movement" would garner a lot more attention if these athletes showed their commitment to rejecting America by burning all of the white males represented on the dollar bills in their pockets and portfolios...

That would really shake things up!
More than symbolism, that would show that these American athletes truly reject the American Dream that has clearly not worked well for them...

"For the master's tools will never dismantle the master's house.  They may allow us to temporarily beat him at his own game, but they will never enable us to bring about genuine change."   (For the record, I don't believe the sister got this right... Maybe she was never properly trained in how to use the tools? Or lacked the creativity to apply their use to her own situation?)