Hispanic High Schoolers Fly Mexican Flag Above American Flag Flying Upside-Down

I received this piece of information from a friend who presently lives and works in California. What's up with this? Is this an act of 'free speech?'

The protestors put up the Mexican flag over the American flag flying upside down at Montebello High School in California.

Speaking of free speech, does anyone remember the screenplay of THE AMERICAN PRESIDENT in which Andrew Shepherd states:

Everybody knows American isn't easy. America is
advanced citizenship.
You gotta want it bad, 'cause it's
gonna put up a fight. It's gonna
say, "You want free speech? Let's
see you acknowledge a man whose words
make your blood boil, who's standing
center stage and advocating, at the
top of his lungs, that which you
would spend a lifetime opposing at the
top of yours. You want to claim
this land as the land of the free,
then the symbol of your country can't
just be a flag; the symbol also has
to be one of its citizens exercising
his right to burn that flag in
protest." Show me that, defend that,
celebrate that in your classrooms.
Then you can stand up and sing about
the land of the free.