It feels like most of your position comes from a place of misunderstanding just what goes into a lesson plan about literature; possibly even a deliberate misunderstanding. Schools aren’t giving children books with smut and senseless violence. These materials are constantly being reconsidered and reevaluated. Vonnegut was something taught when I was in school, and removed right after I graduated.
This comic is pointing at the fact that nearly every book on these lists isn’t there because the content is actually a problem. The lists just have books that some religious group dislikes regardless of whether or not they’re being used.
Besides, somehow the christian Bible is somehow still “approved” while having more rape and violence and men kissing men than any book I ever had to read for school.
I don’t know that I’d really add more. It all depends on who and what you’re protecting against. The only thing that’s secure is something that doesn’t exist.
National level hackers have access to resources you might not be able to think of. And if they really want in, rubber hose cryptography is super effective. But most “hackers” on the Internet? And encrypted zip is often enough to deter them. Not impossible, but you might not be worth the time and effort.
In summary, there is better. Much better than an encrypted zip file. But only you can judge if you’re a juicy enough target to pursue more esoteric protection.