Some people have a fuze missing in their head.
Having that said, I assume having all those CCTV cameras everywhere should be a great help here. As for it being a hate crime, I don't know and it doesn't matter as doing something as this tells me the psycho isn't limited by reason (i.e. he would be looking for an excuse to do it). But it doesn't matter because assault is assault regardless of reason.
P.S. how can someone like this not be caught or ganged up on immediately? It's the biggest, most crowded city with a million cops and a million more people walking in mid-day? Are people in public really that disconnected in NY?