Er, I was being glib. Terminator style robots would be a pretty inefficient way to wipe out humanity. Wrt motive, I would assume that if we are someday killed

Er, I was being glib. Terminator style robots would be a pretty inefficient way to wipe out humanity. Wrt motive, I would assume that if we are someday killed off by our own machines, it will most likely be something akin to an accidental nuclear holocaust.