For more context: Before the pact w Nazi Germany, Stalin asked Churchill how many divisions he could put up for the defense of Poland. Stalin offered 15 and Churchill said he could only put up 2. A division is about 15k troops iirc. So Stalin was rightfully disappointed. Britain was very unprepared. Soviet Union also wasn’t prepared yet for full war with Germany. It should also be added that Stalin also hated Jews, and was absolutely a murderous psychopath