I am currently reading Ken Folletts century trilogy, and am at the end of WW2. I am not sure how historically accurate the books are, but they do describe having historians to assist painting the contemporay picture, so the author must have strived to do it accurately.
The books deal a lot with politics, and are told from the point of view of working class, liberal people. Through book 1 and 2, it is described how liberal (left wing) classes quickly see the horrors of fascism, and are quick to denounce and oppose the likes of Hitler, Franco, Mussolini, and other such groups. However the conservatives (right wing) are described as initially being fond of these fascist ideas, and are very reluctant to see what we now know as the truth, that the fascist regimes were indeed, terrible.
Are there any WW1/2 historians here, who could comment on whether this is the general truth, of if it's really more nuanced than that?
That's sorta true, but exaggerated, or perhaps stated too strongly. To add to that: fascists hated communists, and so communists were one of their prime targets for abuse--the first pr. Communists, in turn, then hated fascists, and became the chief, sometimes only, voice willing to fight them. It was communists in the early 1930s who sent soldiers and weapons to fight the genocidal maniacs of Franco's Spain. This took the form of the Soviet Union doing some such activity, while Americans who were opposed to Franco were more likely to be communist or socialist (but were not necessarily communist or socialist). Fast forward to the 1950s, during the McCarthy Era. Such people who had fought or spoken against Franco came under suspicion as possible communist sympathizers. However, while left wingers, especially far left wingers, were opposed to fascists, that doesn't mean that it was a strong part of the left-wing movement at that time. It was more a hallmark of the far left, not all the left, though you also did not have to be far-left to oppose fascism. Likewise, while fascist/Nazi sympathizers were largely right-wing, it was certainly untrue that most right-wingers were fascist/Nazi sympathizers. Fascism is a right-wing movement. Basically, the extreme right end of the political spectrum is fascism. The extreme left end of the political spectrum is communism.