in historical fiction, is when the characters have to address some issue that is controversial in their time, but which the author sees as having a clear right side and a wrong side. And the author decides that their main character just has to be On The Right Side Of History.
There are ways to have that and still write a solid story, but unfortunately what often happens is that putting the character on the Right Side comes at the expense of nuance and detail in both the character’s thought process and background, and in the setting’s worldbuilding and/or historical accuracy.
Basically there are two awkward things for authors in this situation:
— A historically accurate character might hold approximately the belief we want them to hold, but might describe it in a way that sounds outdated or disrespectful from our point of view.
— A character with a detailed personality and history could explain how they came to hold the “right” belief, in an emotionally plausible and/or historically accurate way, but then we’d have to think about the fact that they used to not believe it and that would be uncomfortable.
(And also, to even get to the point of considering these questions, the author has to themself have thought about the issue in more complicated terms than “x is wrong,” and they have to do the research to know what people were saying about the issue historically and how that differs from how people think about it now.)
These problems are almost worse when it comes to creating villain characters, but it’s late so I’m going to stop here.