Towards the end of WWII, the United States knowingly and willingly killed hundreds of thousands of innocent civilians in the relentless fire bombings of Japanese and German cities, the atomic bomb just expedited the process in Hiroshima and Nagasaki. We in turn became the deliverers of mass death Nazi Germany only dreamed of. The Axis also taught us a thing or two on the joys and institutionalization of torture.
Zionists also became enamored of Axis tactics and methods. The great Nazi art of corralling and ghettoizing target populations was created in central Europe, but perfected in the Middle East; and Israel's Blitzkrieg inspired, lightning fast preemptive attacks and their recurring elimination of innocents killed by accident, coincidence or outright warning are effectively silenced by the incessant cries of "Never Again."
Violence is always easiest to learn, and excuses for using it, easier still.