Sherman's passion is a build-up of a number of things.
Harbaugh giving him a bad review to NFL scouts that dropped him lower in the draft.
Crabtree talking smack.
The fact that Crabtree makes four times as much as him and is a media darling while Sherman has toiled in obscurity before he decided to trash talk.
I think what is lost on a lot of haters is how smart Sherman is. Sure, he is black (oooohhh!) and he wears the dreds (ooooh, gangster!) and therefore haters can dismiss him as a thug. Few know that he graduated second in his class at Stanford with a degree in communications and that he knew what he was doing. He looked right at the camera! He was passionate, but he spoke in complete sentences without resorting to hip-hop vernacular. In his funny post-game interviews, he was even more articulate and intelligent, but people will look at his skin color and his hair, and they will hear his fiery words, which are the climax of years of being dismissed, and they will say, "Angry black man."
He is not an "angry black man." He is an exceptional athlete and a savvy manipulator of his own media, and that is all that needs to be said. And Erin Andrews, as lovely as she is, should have done some homework before thrusting the mic into his face. If she wants to transcend the stereotype that female sideline reporters are just cheerleaders and not real journalists, then she should have known about Sherman's history with Harbaugh and Crabtree and been prepared for the soundbite that she got. Instead, she was shocked and defensive, like a ... well, like a cheerleader and not a real journalist.