The soviets were loosely involved with the north, and did not choose for the northerners how to govern nor dictate their direction. They served as a stabilizing and advisory group, which was beneficial on the basis of the wide communist sympathies across the entire peninsula. It was the Statesians in the south that went against the grain, occupied the south, and handpicked their leaders. Kim Il-Sung was also not an unknown, and was picked by Korean resistance leaders.
Ultimately, today, the DPRK is an independent indigenous state, while the ROK is still colonized by the US Empire. The soviets left the north as was always intended, while the US Empire maintained a permanent presence and explicit control over their military. To call them both occupiers erases that fundamental difference and erases the autonomy of Koreans in the north that ultimately did choose how to chart their own path, which is sadly not the case for the south (yet).

