That said, I think the conclusion that a more skeptical policy toward Stalin would have changed things in Eastern Europe or China is wrong. Unless the US and UK were willing to go to war against Stalin there was nothing we could do to stop the installment of communist governments in countries under Red Army occupation. The US successfully stopped the installation of communist governments in places outside Red Army control, like Greece, Italy and France.
Stalin had little to do with China going red. The very corrupt Kuomintang pretty much lost China by itself despite US support.
Roosevelt was very naive about "Uncle Joe" but bear in mind he threw Henry Wallace off the ticket and replaced him with Harry Truman. True, this was for domestic political purposes, but the far left Wallace almost certainly would not have organized NATO and fought the Cold War.
In a 1952 article, Wallace admitted being duped by communists and turned into somewhat of an anti-communist. He even supported the Allies during the Korean War.