He was absolutely not a nice person, but we shouldn’t forget the suffering the Soviet Union’s population endured as a consequence - could be a lesson for us all.
As for being able to “throw bodies” at the problem, Stalin was actually pretty fortunate that the Japanese attacked the U.S. when they did. Once it was clear that Japan wouldn’t have the resources to go after the Soviet Union in Manchuria for a while, Stalin was able to transfer a massive number of troops eastward to the German front. A couple of years of attrition and things started to look up for us all…