Books often give some of the "why" but that's different from a method which engages with the why. The main change is in going from passively interacting with the material "In the book it says... in my notes it says... in class it was said... on the test it wanted me to recall..." to actively interacting with the material "the book had these why's... the teacher/we discussed these why's... i need to be able to defend the argument of why... I also think... on the test I argued why the fact occurred". Even personally bored while doing it or not it's a better way to learn the material.

You do memorize why's but part of arguing the why's, either to the teacher or in groups, is to add interaction with the details. It may or may not be a barrel of fun but it is, by definition, more engaging. Whether or not that's a personal case is going to be subjective but yes, most people really do like learning via more than rote memorization alone all the time in lieu of mixing it up and engaging on average.

I've definitely had classes where the teacher wasn't able to make the content interesting/engaging - it sucked either way in that case. I'm not as sure the teaching "fails" as much as is "not as good". That students zone out is no measure of a method being universally bad, that the method is single approached and almost all students zone out is a good indicator though and that's what you get with constant memorization only.