Nazi ideals are bad, we can agree.
WWII is especially complex and resistes being reduced to black and white simplistics because of the same kinds of complications that exist today.
Back in the day the UK Royal Family was even more closely tied to their German cousins, many political groups in the UK were sympathetic to Nazi ideals even if opposed to the war expansion .. and the same was true for the USofA.
But, returning to the original point, I see no evidence that Dahl killed literal actual Nazi's.