Because history can’t be presented as objective.
Authors will prioritize some facts over others in how they construct their narrative, two authors may include the same information, but will come out with two totally different ways of telling the same story.
All historical writing is presented as an argument to the reader, authors are trying to convince you of their version of historical events, and will adopt different points of focus to do so.
Stormlight Archive. Sanderson isn’t a perfect author, but that series is pretty dang good, amazing worldbuilding, amazing and compelling characters.