This would explain a lot

I always did very well in history courses, particularly any which required analytical writing and not fact memorizing. Which while I also do very well, is not actually a very good history course (I had a couple which heavily supplemented the text with actual thought)

But I also never opened the textbook. Or bought it.

So a line like this... isn't terribly surprising: "historians tend to rate textbooks as the least trustworthy sources while students tend to rate them as the most trustworthy"

And this is what you get, even basic factual errors by the pound