The difference is that the Soviets didn’t have the audacity to film and document their crimes like the Nazis did. So we have all of these images of what the Nazis did, but precious little visual evidence of what the Bolsheviks did.
Most of the images were from British film makers from April 1945 when most of these camps were discovered/rescued. They even show some of the Nazis being forced to move the naked bodies. The bodies were nothing, but skin and bone. They were starved to death.