Well, he totally hoodwinked FDR and screwed over the U.S., but he’s a hero to the British.
Based on what?
Over there, they see him as a complicated figure with good and bad sides, successes and failures.
Americans tend to see only the shining successes.
If it hadn't been for Hitler and the war, Churchill would have been regarded as an embarrassing failure.
Britons also don't have the affection for Thatcher than American conservatives do.
On the other hand, Americans are more likely to be critical of FDR, JFK, and more recent Democrat presidents than the English.