Prior to Hitler's invasion of Poland, all the elites thought that national socialism and fascism were the wave of the future. Freedom, claimed the well-educated and well-connected aristocrazy*, was outmoded. It was about to be consigned to the dustbin of history, because Hitler and Stalin and those leftist chaps in Europe had found the real deal, government which was truly compassionate and fair.
They took Hitler off their A list after he started the war, because none of them liked the idea of fighting another war so soon after "the war to end all wars", AKA "the Great War"...which we now call "World War One". Pacifism was the watchword of the 1930s, the only way to be chic and to have the elites think well of you. They still figured that socialism was going to triumph, but they realized that national socialism might not be everything they'd said it was. Joe Stalin, now, he had the real deal....
Understand that they didn't think badly of Hitler because he was a socialist; only because he was a warmonger. Here was someone who had been injured in WW1 and who now was starting a new war in Europe; hadn't he learned anything by fighting in the first one? He was doing so well at implementing socialism in Germany, and absent Hitler's aggression they would have pointed to those successes as evidence that socialism worked.
But there's a problem with socialism that its proponents refuse to understand, because it guts the whole works: government can not create wealth; it can only consume it. And socialism is nothing but government. Wealth is economic surplus, and economic surplus is generated only one way: via effort expended, over time, by people.
Germany had to attack Poland, and other European countries, because it needed plunder to keep the game going. That's why all socialist systems are irredeemably expansionist. They have to be. Notice please what happened to the USSR when its expansionism was curtailed by geopolitics--not just NATO and the threat of nuclear war, but the simple geography of Europe itself played a factor. The USSR could not absorb more countries without causing a major war, and Russia and China are heredetary enemies even though they were fellow travelers...and anyway there is no infighting which is more bitter than when two socialist groups decide to become one and there is an extraneous set of thugs. (Hint: one set of thugs is liquidated. There can be only one top dog. Ask Leon Trotsky how he liked his retirement from Soviet politics....)
The USSR had nowhere else to go that could be accomplished as easily and cheaply as, say, its acquisition of Czechloslovakia. When the economic machinery of the USSR began to sputter in the late 1960s, it was the beginning of the end for them.
Hitler's socialist programs kick-started German industry after the disastrous hyperinflation of the Reichsmark, and given a rational approach to his territorial aspirations we might have had two forms of totalitarianist socialism to face down in the 20th century rather than one. Nazi Germany could have continued as it was for at least a decade before it really needed to absorb another economy, but Hitler's own naked desire for dominion short-circuited his patience.
Anyway, Germany had been a highly industrialized nation before WW1, and before the Weimar Republic fiasco. They didn't have to rebuild anything physical; just confidence in the German economy--and the lack of confidence had been due to reparations and Weimar inflation, not because Germany had lost its ability to produce things of value. Weimar Germany was nothing like modern Zimbabwe, which can't even feed itself; in Weimar Germany there was plenty of bread to be had at 50,000,000,000,000 marks per loaf. The problem was getting that 50,000,000,000,000,000 marks to the store before inflation raised the price to 500,000,000,000,000,000,000 marks per loaf.
(See what I did there?)
But because Germany was socialist--and because socialism was the latest and greatest thing in the early 20th century...why, everyone who's anyone advocates socialism as the system of the future!--the people in Hollywood naturally loved Hitler. (At first.) Hitler was a perfect example of how great socialism was. After all, look at how it fixed Germany!
Then Hitler showed his true colors. People describe Hitler as a "madman" but I don't think Hitler was actually crazy, because truly crazy people are incapable of keeping their shit together enough to do big complex things. I think Hitler was a psychopath, yes, and I think he had some weird ideas about race, but that doesn't make him "crazy" exactly. Fucked up and wrong, yes, but not crazy.
That's kind of the problem.
When Hitler started doing his anti-Jew stuff, that was when American aristocrats began to turn away from him. (The real die-hard lovers of socialist dictators didn't sour on him until he attacked Russia in 1941, but that's another story.) 1939 was the first time the world saw that the "shining future of national socialism" was actually a coat of wax on a turd.
The final problem is that socialism is socialism is socialism, regardless of the adjective that precedes it:
...and the people who support socialism will turn away only from the socialists that make socialism look bad. That is why Hollywood supported Hitler before 1939, and turned anti-Nazi afterwards. It's also why any time you say "Nazis were socialist" to a socialist, you will end up being threatened with violence. Nazism is socialism and it led to the end that is inevitable with socialism: mass murder, oppression, death, and destruction.
It cannot be otherwise.
*I swear to God, this is a Freudian slip. I did not mean to write the word thus, but I'm leaving the typo it because it's right.