"... an inalienable American right..."
As is the right to protest in whatever peaceful means one chooses.
I know of people who stand for the Anthem but who refuse to vote on measures that would increase benefits to returning veterans. To me that is simply an empty gesture. Moreover, IMO it takes far more courage to not stand -in protest-than to stand along with everyone else.
BTW: I stand out of respect for my dad who lost his life during WW 2. But I take no offense to those who choose differently.