I don't believe that it was mere coincidence that Funakoshi watered down karate by de-emphasising strikes to vital parts of the body, that Kano who once was enthusiastic about including atemi in judo, decided to abandon atemi except in a few kata and that atemi and vital pressure point manipulation were de-emphasised when aikido developed from Daito Ryu. These all seemed to occur around the middle of last century. The martial aspect of these arts had to be de-emphasised if they were to continue being practised.
In terms of the previously mentioned analogy of a finishing atemi with the nuclear bombs that were dropped - yes a good analogy: atemi can finish a conflict quickly and decisively and avoid the loss of life of the person/s being attacked by a foe who otherwise would not surrender easily.
OK, Kano died in 1938, so it would have been pretty hard for him to modify anything at all after the war.
Certainly, things were modified - and who modified them and why is an interesting discussion - but there was certainly no requirement
that they be modified by the occupying forces.