As economically and socially evil as international socialism is it tends to be quite good on warfare; though for misguided reasons. Also relatively weak governments, such as the Soviet Union, are pacifistic for pragmatic reasons. Every major advance of the Reds was aided and abetted by the West.
There are some obvious errors in the piece:
#1 Karelian Isthmus was actually ethnically Finnish. Viipuri was second largest city in Finland, but after the war its population was evacuated to Finland.
#2 Actually the USSR won the war and the Finns were forced to cede territory.
Far from being trusting Stalin was on high alert and in the midd and late 1930s repeatedly ordered the size of the Red Army be increased. The size of the military was tripled, the number of planes, tanks etc built was staggering. After the Winter War fiasco and the simultanous successes of the Germans he in panic mode ordered an enormously ambitious restructuring of the Red Army - the exact opposite of trusty, sleepy Stalin. The problem was that he had utterly convinced himself that attack could not take place in 1941, but only in 1942. So when the Germans attacked the Red Army was a huge force on paper, but not very combat capable since it was in the middle of megalomaniac communist style reforms. This was the reason for the early sucess of the Germans, not Stalin’s naivete. (Glantz: Stumbling Colossus for more on the state of the Red Army.)
I applaud the article in general. Stalin was perfectly happy to expand his power territorially, however he was the the ultimate anti-gambler and only ever moved when he thought the outcome was absolutely certain. If he was not, he prefered to sit on the gains he had already made. He had huge capacity for appeasment and bent backward to appease Hitler and avoid anything that might be seen as provocation in the 1940-41 period. The post-war appeasment of the US was merely a rerun.
The military that the Soviet Union had at the end of WWII was an awe inpiring force, let no one underestimate that. It was partially built with the help of the US. The T-32 was a rejected, superior, American design, and western logistics kept the Soviets going. So close to the brink of destruction did Russia come that their generals became experts in the use of combined arms out of necessity long before the American military did. The Soviet army that reached Germany outnumbered the western alliance by about 2 to 1.
In its time and place, the WW2-end Soviet Military was a monster (though not one with a chance in Hell against the US). But it pretty much became a dinosaur due to its lack of capital.