If this kid was as much trouble as implied, they could have found many other ways to expell him.
Besides, I have scribbled much, much worse things in notebooks than gang symbols during a lecture on "our diverse ecosystem" that went on about three days too long.
What difference does it make? I simply think that people shouldn't rush to judgment against this school district simply on the word of this kid's parents. Many parents today are of the 'no responsibility' and 'my child right or wrong' philosophy, and nothing that they say can be taken at face value.
I agree with dazzleman. It seems this kid had a background of problems that his parents, though we are not certain, did little to tackle. It is only now that they kick up a fuss. This story has to 'stew' for a few days before we can decided if it was a heavy handed action or not.