It's amazing how many widely-believed modern myths can trace their origin to the assertions of (often) a single author that nobody bothered to fact check. It seems to be more common when there is a religious element, but that's just my anecdotal observation.
For example, there's the cultural image of Rosa Parks being a quiet, mild-mannered woman who one day decided not to put up with oppression. It makes for a smoother media story. But rather, Parks had been involved in activism and her actions were part of a calculated campaign: [ https://www.washingtonpost.com/posteverything/wp/2015/12/01/... ]
Modern science-lovers have a simple progress-oriented narrative about people like Galileo and Hypatia, but the historical details are nowhere near as straightforward as the tales would have us believe: [ http://tofspot.blogspot.com/2013/08/the-great-ptolemaic-smac... , http://tofspot.blogspot.com/2015/02/hypatia-part-i-mean-stre... ] The triumph of Science over Superstition is one of the founding myths of the modern era, and so of course the rough edges or complicated bits get filtered out in the retelling.
Same with the Paul Revere bit you mention. If there was no interest in the Revolutionary War to the average person, the few stories about Paul Revere would have kept their details. But because it's part of the founding myth, part of the civil religion of the US and something we tell to children, it becomes simplified and polished into digestible pieces.