When your protest uses violence, you will prosper the very tyranny you claim to fight.
What we see in Ferguson, Missouri shows this exact point. People are angry and riot. This is not the first time this has happened in the US. Local police forces see this and worry it will happen in their towns, so they collect more and more military style equipment and tactics. This concerns many citizens and the loop becomes a vicious cycle. Love and Peace should be our first recourse, not violence. The former can overthrow tyrants, the latter will be used by tyrants to increase their grip. True and lasting change is created one person at a time and spread through Love.
Instead of turning to hate, live with Love. Seek the path of Forgiveness in all things. Despise not your Enemies. Love them and stand on Principles. Hearts are Converted with Love, not hate.