There you go, contradicting yourself from one sentence to the next. Vtech was the deadliest shooting ever, and it used (by your logic) "low power" 9mm and .22LR cartridges.They would have helped prevent Vtech and Arizona and maybe Aurora.
Sandy Hook is a good reason to limit the overall power available, period, in firearms.
Maybe Glock can design a karmy-approved low-lethality G17.