Has kneeling for the Anthem been found or proven to be protected symbolic speech?
https://en.wikipedia.org/wiki/Symbolic_speech4
The courts have ruled on many of occasions and on stuff arguably more offensive behavior like for instance burning of the flag that such actions are protected by the first amendment.
That is along the lines of what I have read as well. However, will or should the courts rule specifically on kneeling for our Anthem? In my opinion: yes, they should--all the way to the Supreme Court. Should kneeling for the Anthem be socially acceptable? In my opinion: no.
You know, taking a knee during the anthem doesn't really bother me much at all. And, I'm retired Navy with over 20 years of service. When I swore my oath of enlistment to join, and each time after that when I reenlisted, I pledged to support and defend the Constitution of the United States, against all enemies, foreign and domestic.
Supporting and defending the Constitution means that I also support and defend what it contains, and peaceful protest and free speech are there, which means even if I don't agree with what you have to say, I will defend to the death your right to say it. And, most military people that I know feel the same way. Granted, they may respond to your free speech with a bit of their own, but they will defend your right to free speech. Nothing in that oath was mentioned about the flag or the anthem, just the Constitution.
So, no, don't come up with the bullshit reasoning that kneeling during the anthem is disrespectful to the troops. What is more disrespectful to the military is taking away the rights in that document that a lot of them served to protect is more disrespectful than taking a knee. I'm kinda glad that Kaepernick and Nike both feel secure enough in the rights that I spent all my adult life defending to use them.