The clever conceit behind James DeMonaco's 2013 sleeper hit "The Purge" was not that American society had resolved its crime/inequality/population problems with an annual free-pass-for-murder "purge." It was that this hell night came home to roost on isolated, gated suburbanites, ostensibly liberal people above this annual bloodletting, immune to its impact but benefiting and even profiting from the mayhem — until it invades their community and their homes.