Was FDR a Fool?

I’ve always known that Roosevelt gave away the store to Stalin at Yalta, and have suspected him of being a Communist sympathizer (as his wife certainly was, to the point that the Soviets discussed approaching her to spy for them). But this Study In Intelligence by the CIA, which describes how Roosevelt allowed himself to be spied upon by Stalin both at Teheran in 1943 and Yalta in 1945, makes Roosevelt appear to be even a worse chump than I thought. This sample Roosevelt quote, addressed to the U.S. Ambassador to the Soviet Union, who tried to warn Roosevelt against Stalin, is priceless:
“Bill, I don’t dispute your facts; they are accurate. I don’t dispute the logic of your reasoning. I just have a hunch that Stalin is not that kind of man. Harry [Hopkins] says he’s not and that he doesn’t want anything but security for his country, and I think if I give him everything I possibly can and ask for nothing in return, noblesse oblige, he won’t try to annex anything and will work with me for a world of democracy and peace.”
It would be hard to imagine a more stunning combination of arrogance and ignorance. Franklin Roosevelt’s reputation has declined in recent years, but it hasn’t declined anywhere near enough.