Could have said the same thing about the Boston Tea Party though couldn't we, just a bunch of disaffected A-holes and rent a crowd faithful.
The fact is through out the world civility generally gets people nowhere, France didn't over throw its aristocracy by writing letters to the newspapers, the USA didn't become the USA by waiting for King George to see reason and the Magna Carta didn't come into being through a magnanimous gesture by King John.
You can not have a police force shooting its own citizens at a rate of greater than 1 a day and think people (especially the groups that are being shot) are not going to get pissed.
So yes those protests are both good and needed they are indications of people prepared to stand up for a cause and while it can be misguided it is not a bad thing and in many ways they are a true form of democracy while blind obedience to authority is not.