That totally flew over my head, sorry! Violence in the train didn't even occur to me while reading the comment, I thought they meant something on the lines of "the driver will have better visibility when opening/closing the doors on the front train so it's safer to go there so they cannot accidentally close them on me" or something similar. Now of course they meant there's less chance of violent behavior near the train driver, and the comment makes a lot more sense for me now.

Note: I do take the train daily, just I live in Tokyo

American cities are less safe, but the NYC subway is quite safe. Train operators will never leave their cabin no matter what (part of the rules of the job), and so do not enhance the safety at all.