You're giving a wonderful example of the phenomenon I'm discussing. You learned, probably in grade school, about McCarthyism and whatnot and now you're ironclad convinced the whole thing was a paranoid fantasy conspiracy theory or if there is any truth to it at all that it was insignificant. Meanwhile, there are a large number of known communist traitors and spies from the era[1] and probably many more that weren't discovered. It's been the better part of three decades since the Venona Papers were declassified. This is ironclad history[2].

[1] https://en.wikipedia.org/wiki/List_of_Eastern_Bloc_agents_in...

[2] https://en.wikipedia.org/wiki/List_of_Americans_in_the_Venon...