Graffiti prevents you from looking at the bleak, clean surface. And this has already been cleared up, while graffiti often requires more then a few keystrokes. Graffiti can really destroy surfaces, and they will never be as before. Then there's tagging, which is just the equivalent of dogs peeing everywhere; as opposed to people actually trying to make a statement... to the law that distinction doesn't even exist, to me it does, and it does make a difference.
This is criminal vandalism
Graffiti isn't exactly lawful, so that's quite redundant? Unless of course you wanted to stress that your outrage is completely guided by "is it lawful", as opposed to, say, "is it good".
Oh, and unless you're a student of MIT, or anyone who was actually inconvenienced by this, or at least know someone who was, I really wonder where this is coming from, and where it's supposed to go. I mean sure, by all means criminally persecute a bunch of "children", that surely must be the ticket, that's the lesson here. Lock them away!