Necessity!

The Great enemy in the West was immediately replaced; Communism was on the rise and arguments can be made that the Western Allies had decisively lost the race for Europe, many traditionally pro-Western nations, such as Poland, were now essentially Soviet Satellites.

The chance of a Soviet invasion, in contrast, of Hokkaido (Japan's northernmost Island) was slim to none, but was on the minds of the occupying Allies.

Finally, in terms of Officers; the shattered remnants of the Wehrmacht had many 'denazified' Generals who could be trusted to help reform an effective and defense-capable German Bundeswehr, and many men who served in the Wehrmacht found successful careers in the newly-formed Bundeswehr.

In short, what the Soviets wanted/were perceived to want, was in Europe, not the Pacific.