This song is about being at skool, it about being different. The boy is bullied and wishes he could fight back, but he keeps his head low.

Umm... well, no. It's really about the general stereotype of the hippie.
"Crossing in between greens Just because you want to Not because you ought to": The greens are referring to all the unnessecary cleared out space for things like malls, which hippies opposed.
"They can never feel your pain, Neither can you": Not many people really cared what hippies had to say, and hippies couldn't feel their pain cause they were always so loaded up on drugs.
"That was you across the yard, Throwing brownies at his car": Some hippies believed that cars were corrupting, and a nusance to the environment.
"Keeping your head low, Around the car park you swing low": From what I understand, (i'm not really sure on this one) hippies would actually slice tires of cars in car parks, and to not get caught they would keep their head low. Whether I'm right or wrong, I do know this... that guitar at the end is beyond the infinities of awesome.