Execution is not the code, but how do you decide to do every part. "Idea does not matter, execution does" always meant: "big generic ideas don't matter, it is how you organize it in the myriad of details it is composed of (in a given incarnation of the general idea) that matters."

But why aren't lower level "ideas about execution" more clearly expressed in code? Or at least pseudocode?

Many of us would struggle with our reading comprehension of an English description of an algorithm. But the pseudo / actual code? Much easier to reason about.

I'm not saying you should review even 90% of code. But it feels like an arbitrary line to say "never look at code". It's like never taking a wrench to a car to look at what's built to see whether you trust the car factory.