Simply put, they have no idea what they’re talking about.

Stalin took credit for defeating Nazis (after carving up Poland with them first, but who cares about minor historical details) and was leading this big global superpower that could stand up the The Evil West (while also crushing every other leftist organization that didn’t bend the knee, but again, minor details).

And from there it’s a pretty simple leap to the world being divided into the Good Camp and the Bad Camp. The US is clearly in the Bad Camp (which is the part I don’t argue). The USSR was against the US. Therefore it must be the Good Camp. The idea of multiple evil people opposing each other is a bit too complicated for them.