> Obviously a door with a handle shouldn't be a push door, I don't really think you need to write a book about it.

It’s common to illustrate principles with examples that appear obvious, i.e. that everyone agrees on, so that after having it conceptualized as a principle, you’ll apply it in less obvious circumstances. Many things are obvious only in hindsight.

> And the types of people creating bad design are generally constrained by cost, time, or practicality, not necessarily by education.

That’s not true, because a lot of flawed design is being promoted and defended in public as the thing to do.