The works you refer to are history books written from a specific view with the point, it must be said, to make money for the authors

These aren't works of popular fiction, DtG - they are seriously researched works of social / cultural history by authors who remain essentially, and impressively, impartial throughout. One hopes their efforts earned them a working wage, but I doubt the authors were looking to cash in on that academic folklore market which has attracted so many with its allure of filthy lucre.