Chalk on the sidewalk isn't vandalism. The next rain or incontinent animal will take it away. It's not damage in any real sense. The law in the banks sense (the only one that applies here) is that it was damaging in that it offended their sensibilities; sorta like slander or defamation or the like. So he'll get more time than the bankers who stole my and a whole stack of other peoples 401K's and retirement savings. You're right: the law is clearly balanced.
Now lecture me on not saving properly for my retirement. It'll just finish the kabuki properly.