This is a two-parter... America entered the war after Pearl Harbor in the beginning of December 1941, and at that point in time the US was still building up its forces as FDR began the draft in September 1940, and the US was in the process of switching manufacturing towards war materiel, and even so the weapons that the US produced in the period of the late 30s through 1942 somewhat behind the other powers that had already been at war such as fighter aircraft and tanks. Not only that, but the US had to transport all of their infrastructure across the Atlantic and continue to build up and train manpower. How could Stalin have expected the West, particularly America, to open a second front immediately in France when the US was not on a total war footing at that point, the fact that they had to transport everything across the Ocean, etc.? If anything, France and Britain could have done more in 1939 when Germany was in Poland. Secondly, The Western Allies eventually waged war in the Mediterranean, the air, and the sea before Normandy, all of which took German men and machines away from the Eastern Front. The Germans did transfer experienced divisions to Italy, regardless of the size of the front, and with the air war, the substantial German air materiel was for homeland defense, giving Russia air superiority. Why did Stalin not consider these early contributions as satisfactory, especially when the USA was not in a total war footing when attacked at Pearl Harbor and subsequently entering the war. German units were transferred to both the Mediterranean and back home for the air portion, which helped Russia before Normandy, in which the West knew they were attacking a heavily fortified area by sea that the Germans knew was coming at some point, though unsure of the location/time. Germany and Russia were dictatorships that had huge land armies and ground equipment built up as part of their regime. If the West was going to attack France by sea with all the logistical planning and man and materiel power involved, the right decision was to make sure they were sufficiently built up, trained, and gained experience in other areas first.