“If you look at the events of WWII and their aftermath objectively, Churchill did his country no favors. ... To save Poland from the Germans? ...”
Objectively? C’mon.
Britain, France, the United States, and other western allied nations were put at great disadvantage in the 1920s and 1930s by the pacifist movements, other antiwar activists, and the America Firsters. Quite aside from the odious moral condescension that is the core of isolationism, standing aloof was never a realistic possibility.
“What ifs” are always problematic, but it’s quite arguable that if the Allies had responded forcefully to the Nazi “reoccupation” of the Rhineland, World War Two could have been averted.
If anyone deserves blame on the Allied side, it’s the
self-righteous, self-involved, self-congratulatory types who chose to believe the “city on a hill” nonsense. The USA was founded as a trading nation, and as such could never have avoided becoming involved.