The main purpose and effect of the military intervention the US undertook near the end of the war in western Europe was to preserve capitalism in Europe, which required them to shelter and preserve fascism. Had they not intervened, Europe would have “fallen” to socialism. Therefore, the net effect was the protection of fascism in Europe. You can tell this because of all the actions they undertook to preserve fascism and put fascists into positions of power after the war. The point isn’t that they didn’t fight the nazis, the point is that they fought them to preserve capitalism, and therefore preserved fascism. We can agree to disagree.