You underestimate how hard writers are willing to try to worm their way around that and how inexplicably willing people are to go along with their circuitous and tortured logic in the name of keeping the official kill count at zero. But yeah, there is literally no chance that at least a few of them have not died. Even if Batman didn't kill them on the spot they still died due to complications from their wounds. Infections, internal bleeding, organ failure, etc. There is no such thing as a harmless knock-out. That's how people get brain damage. But the power of the willing suspension of disbelief says that Batman is so precise that he can consistently beat legions of criminals within an inch of their lives over and over without a single direct or indirect casualty.