Hear me out, I've inspected the tiles and the "handwritting" of sorts and it's message and I swear I know who the guy is. There is this "crazy" guy who hangs out on the corner of 18th and Market St. in Philadelphia with signs so similar in message and style. Considering there are 60 of these in Philadelphia, I would bet everything it is this guy. He's an older gentlemen and he's very easy to spot considering how much signage he wears on himself. Trust me, mystery solved.