Ta-Nehisi Coates' post on the problems besetting the Tea Party protests is characteristically excellent. All three critical points he makes are really solid:
(1) The civil rights movement was effective because it knew how to choreograph a protest, to maximize its effectiveness while minimizing the potential for embarrassment. The participants were drilled in proper protest behavior. So while the media may have been rearing to go with "crazy Black people run wild in the streets" storylines, the protesters themselves saw it coming and reacted accordingly, defusing the threat.
(2) Of course folks opposed to the Tea Party agenda are going to try and paint their protests as bad things that the rest of the country should also think are bad. That's their job. It's the Tea Party folks' job to behave in such a way so as to make that tactic unfeasible, and it's their fault that they're not.
(3) The Tea Party is probably institutionally incapable of remedying this problem, because if you weed out the crazies, there's nothing left there. The sort of folks that cause the tea party to come off as extremists to the bulk of the American public aren't fringe actors, they're the base.