I do sing the anthem (off-key, and with a suspect falsetto for that high note. Hey, we can't all be Prince! Some of us have to be Barry White. OK Biz Markie).
But I'm making an informed choice, because I know white US history.
I don't judge Black folk or folk of any color that choose not to sing it, as "un-American" or "un-patriotic."
For some folk, American patriotism means unquestioning loyalty to the ideals of a white supremacist America. For them, anti-racism itself, is anti-America.