When we compare the aims and actions of both countries, it's clear that the Soviets genuinely wished to help establish a state for the Korean people, and that they did not intend for the division to be permanent. The US Empire in fact was the one to split the peninsula. As you said, the Soviets were active for less than 5 years in the north (beyond the eventual trade and fraternal relations). Occupation to me implies that they were unwanted and staying anyways, neither of which are true for the soviets while both are for the US Empire.
I think it's reasonable to critique the level of influence the Soviets had, but such a critique cannot be made to equate the role played by both the Soviets and the Statesians. They had entirely different methods, aims, and actions. In reducing both to "occupiers," you make it seem that the Soviets too wished to establish a colony, when this has proven false. In fact, it was the Soviet Union that insisted that the trusteeship be short, and it remains true that the Soviets upheld their commitment to aiding the establishment of a Korean state by and for Koreans.
To simplify this to the same western chauvanism that the US employed in colonizing the ROK minimizes the gulf between how the two countries treated Korea.

