This is exactly it. There is a literal fight that the protests represent, that some commenters here (no offense intended, we're all on the same side) can't see past; and there is a symbolic fight.

The symbolic fight defines how we think of ourselves - which I do think is important, that we are the true voice of the American project - but also how the rest of the country views Trump's illegal use of military troops. The Mexican flag does not help either symbolic goal. It's counterproductive.