So why Hitler in particular? There's a lot of people to choose from. American Nazis are literally Brits larping as Germans.
Germany is a nice place. It's pretty weird as a Brit, since Germans are practically identical except for a few giveaway traits.
Instead you choose the one most antithetical to your nation's creation.
Hitler didn't want some white world - he didn't even want to spread Germany's people outside of Europe.
He wanted to conquer the lands to the East - to the border with Asia.
Britain, on the other hand, spent centuries securing, cultivating and expanding territory across the planet.
The only saving grace of Nazi Germany was its war against the USSR. Regardless of all you think, he did invade every colonial state, to America's delight as he had destroyed the competition.
Maybe from an American perspective, since America stabbed Britain (and Ireland) in the back immediately after the war ended, Hitler wasn't "so bad" - but for both us and the French, the issue wasn't that he was a Nazi, it was that he was the German head of state. Any action which would benefit Germany would harm Britain, and both sides knew it.
Why don't we bring up actual American values and dispel the myth of America's rise to power - as soon as Britain was weakened by Germany, as we feared from the beginning, both the Americans and Soviets, "im gleichen Schritt und Tritt" as the Germans would say, set to work dismantling and intentionally sabotaging British dominance in the world, and immediately bargained using stolen property for alliances.
Turkey, for example - what price did America set in exchange for Jupiter missiles in Anatolia?
Why, Germany, of course; the Gästarbeiter program was created by America to allow Turks to work in Germany, half a million initially, in exchange for their coöperation.
The severely crippled British Empire? Up for grabs, Pakistan up first. Keep the USSR out of India and you can have all the white girls you want.
France? No Soviets in North Africa, instead, North Africans in France.
America brokered every deal which lead to our current situation. Britain was absolutely right - America was using Germany in the same way that the USSR was - to weaken their rivals and seize power.
America even rejected a full invasion of the USSR - something which Churchill and Hitler agreed on!
Instead America waited until over a million Germans were starving.
America waited out the war deliberately until the Dutch, French, Belgians and British were weak enough for America to move in and expel them from territories in Africa, Asia and South America, using Hitler as a weapon to destroy their rivals. Then physically removed the settlers, and, in one of the most disgusting manoeuvres in history, sold countries whole to increase their influence in Africa and Asia.
