There are a lot of things the Nazis got right, but also a lot they got wrong. Had they not gone to war their economy likely would have utterly failed by 1943 due to the shenanigans and fuckaroo they were pulling.
As far as "why do we still act like the Nazis were wrong/evil", that has a lot to do with the Post-War Consensus. The First and Second World Wars started early on in what I call the "Progressive Era", where Western culture was shifting rapidly to the Left and away from many of the traditional values for European and American culture, such as honor, duty, patriotism, masculinity, Christian morality, meritocracy, etc. The consensus after the war, pushed by so-called "progressives" in politics, academia, news media, and popular culture, was that the Nazis and by extension Right-wing politics were the worst evil that humanity had yet seen. There was little to no effort to analyze the situation with any fairness, nuance, or honesty.
As the memory of WWII became a more and more distant memory, the Nazis moved away from being part of living memory and instead became the big bad guys in movies, television, books, and eventually video games whenever the creators felt using the Soviets was too cliché. Whenever you needed a truly evil villain, have them be a Nazi who escaped justice. Maybe a Mengele-esque mad doctor or something.
So now everyone is conditioned to see "Nazi" or "Fascist" as shorthand for "evil". Hippies would call police "Fascists!" whenever they got busted for smoking grass or selling acid. They moved away from being real people and became cartoon villains, like Doctor Doom or Lex Luthor. Any time someone started pushing politics a little to close to the Right for comfort, just ask if they're a Nazi and when they plan to start putting Jews and faggots in the gas chambers, and that would shut them up right quick.
However, now that the Nazis are so far back in our history and there are few with actual living memory of those days, that means the younger people don't have the same fear and loathing of them that the older generations have. These young people have been born into and lived their whole lives within the "Progressive Era", and seen the results of mostly Leftist politics. The feminization of society, the utter lack of patriotism, globalism, the gutting of industry in most Western nations, the hostility towards traditional masculinity and demonization of men, the rising crime, the moral decay and social decline, mass migration of third-world savages into Western nations to leech off the native populations, and the death of prosperity and upward mobility for regular people.
They've seen their politicians selling out their nations and their fellow citizens year after year, all while continuing to regurgitate the same old tired Leftard talking points. Eventually they think "Well, if this is what Leftist "progressive" politics has to offer me, then how could Right-wing politics be bad?" Suddenly the spell of the Post-War Consensus begins to break for more and more people. It's still in it's early days and it's going to take a while for enough people to wake up. It's painful to open your eyes and realize that everything you've been taught going back several generations is a fucking lie, so some people are going to struggle before they can finally allow themselves to accept it. But I think we are experiencing the beginnings of a massive cultural shift in the West much like what we experienced in the late 1800s and early 1900s when the Progressive Era started.
