Why are these demonstrations happening? Why don't the demonstrators accept the verdict of the jury? This is why, IMO:
Yes, young black men use the N-word among themselves ad nauseam--but you can't.
Yes, young black men kill each other up all day every day all over the country--but you can't.
Why? Because to many of these people you, if you are white, are the enemy, into whom the many undoubted ills of Black America are projected. This slaying is a bitter reminder of times past, when it was white people regularly killing young black men without a second thought and little fear of consequences. Nevermind that it is now other young black men who hold black life cheaply. The demonstrators don't look past the symbolism, the imagery--which admittedly is potent indeed. The disconnect between the jury's verdict and the demonstrators' anger tracks the disconnect between justice and so-called racial justice.
My congratulations to the court and jury for arriving at IMO the correct verdict without fear or favor.