See, because of the learning experience I steer away from non-fiction books. I am deeply afraid of the narrative red string applied to reality - connecting a tiny subset of the observable data points to a simplified interpretation/explanation of the whole. If I want to learn, I look at raw data, reports, white papers, etc.. Because authors always have some bias or other, especially when they decide to write a book-length document. (Except, of course, a data catalog of sorts, like a lexicon or other exhaustive enumeration - those are usually a good starting point) I have enough of my own biases, and rather get a diverse set of inputs on a topic. Fiction though? Sure, let's suspend our disbelief and have some fun.

Edit: to clarify: this is not me accusing authors of non-fiction books to always have some evil agenda to push. One human only has limited capacity and things will always fall through the cracks. Do your own research with the constraints you actually care about, if you can.

Yes, everything outside of personal experience is somewhat fictional - one probably wouldn't agree with the biases, assumptions or assessments of any author/content creator.