If you think your dad was sent to fight against the Nazis for ideological opposition, i have bad news for you. Maybe he personally fought out of that motivation, but must countries at the time were either fascist themselves or on the edge to fascism.
If you look at the US there was the ongoing genocide against native Americans, the racial segregation, eugenics, despicable human experimentation carried out on minorities, concentration camps for Japanese during WW2… Even the pledge to the flag in the schools was something Hitler admired and copied. Until the German Nazis became unpopular in the US the pledge to the flag with done with the “Bellamy Salute” that is the same as the Nazi salute. en.wikipedia.org/wiki/Bellamy_salute
What is different though is that after WW2 it was understood which social problems, in particular fucking over the lower and middle class, create the breeding ground for fascism to be successful. Since the 1980s with Thatcher and Reagan and then the neoliberal wave over Europe, we had 40 years of deliberately empowering fascism. Now they reap what they sew.