What's the point of the Soviet "Policy of Collective Security" focus
Playing as the Soviet Union, I am trying something different from the historical path, i.e. stopping Germany during the invasion of Poland in 1939.
I thought the "Policy of Collective Security" focus tree would be a good path towards that. However, it doesn't really seem to help. The focus "Seek a defensive Pact with the Allies" makes the Soviet Union and France guarantee each other, but then France goes to war with Germany because of the invasion of Poland in 1939, and because that is not a strictly a defensive war for France, I am not called into it. And by the time Germany invades me in 1941, France has already capitulated, anyway, so the guarantee doesn't help me there, either.
There is an option for Poland to join the Soviet-French defensive pact, which obviously would help, but in my games, Poland always refuses to join (they'd rather be gobbled up by Germany, it seems!).
Am I missing something, or is the "Policy of Collective Security" focus tree utterly pointless?