I think it entirely depends on what audiobook you're listening to. If I'm listening to something that's lower complexity or aimed at younger audiences (e.g. The Martian by Andy Weir or The Hitchhiker's Guide to the Galaxy by Douglas Adams), I can miss bits and pieces of the narration without losing too much of the story. As long as you don't lose track of several uninterrupted minutes at a time, you'll probably get most of the relevant context. The same applies if I'm in the mood to listen to a story that's already familiar to me, like Lord of the Rings.
It definitely becomes more difficult to multitask with harder reads; which is where I prefer to have a book in hand. I'll have to rewind several times per chapter to catch everything. Though it's still doable for some, I'm sure.
I would think that the distinction lies in the time it takes to reach consensus. An individual person's moral values may change rapidly without the need for external validation. A book club may take a few weeks of debate over a heavily philosophical book to modify the perceived moral values of the group as a whole. But stretching large moral shifts across an entire populace would probably take more time and a more concerted effort to accomplish. New ideas or values need time to be sorted, whether they be picked up into the mainstream view or dropped into unfavourability.
Can you expand on why you think reading plain markdown is hostile? For the vast majority of my Obsidian vault, I could open the markdown file in Notepad and it would be just about as readable as it is in the editor. Of course, you lose the visual effect of the styling, but it's still perfectly legible.
It definitely becomes more difficult to multitask with harder reads; which is where I prefer to have a book in hand. I'll have to rewind several times per chapter to catch everything. Though it's still doable for some, I'm sure.