The JW antipathy toward Freemasonry comes from the same source that produced a lot of the more far-out fringe beliefs that descended from American Evangelicalism in the 1800s. That was the same era when hoaxes like the "Catholic = Babylonian paganism" got started. Centuries of amity between Evangelical Christianity and Freemasonry became far weaker during that time. In many ways, it was like the creation of the Muslim Wahabi and other rigorous sects--Rejection of all authority other than ingroup interpretation of Scripture, rejection of society as a whole as being "innately satanic", ultimately rejection of any who fell into "not-like-us". In the USA, this was an era of great paranoia about "foreign influence".