They made promises to all sides. They lied to everyone. They closed the gates dooming millions of Jews to Hitler. They executed Jews. They coached Arab armies in their 1948 attack on Israel. I could go on.
As I see it: enemies are enemies. You know where you stand. Someday, maybe you will even reconcile. Lethal malicious treachery from supposed friends is damnable for eternity.
Some of our greatest friends and allies today are the same people who commited the worst atrocities in the 1940's. I do not excuse their behavior then, but I will not hold the current generation responsible any more than I hold contemporary Americans responsible for slavery.
And as for closing the gates in WWII, do not forget how much the British themselves suffered at the hands of the Nazis. Were it not for their courage and resolve, America might never have gotten involved in the European War.
No nation is without sin.