I was educated about the conspiracy theory of history by Eric Butler, who said that the alternative was the idiot theory of history, of unconnected random happenings. The idea that agents plot and plan in secret, is in fact a scientific idea, having a clearly definable causal mechanism, rather than just assuming random associations. In a classic piece at Mises.org, Murray Rothbard gives a spirited defence of the conspiracy theory of history, a fine presentation.
https://mises.org/library/conspiracy-theory-history-revisited
