A computer can basically do four things: Load a value from memory, store a value into memory, add two numbers together, branch to another list of instructions if a number is 0.

So, if you understand those operations, you understand everything about computing, right?

The problem with the financial world wasn't that they built on incomprehensible primitives. The problem was the incomprehensible structures they built with them. Just like programmers and programs. A basic understanding of the primitives is necessary but not sufficient in either case. And the programmers have an advantage that all the source code they are running is in one place; to understand the financial system technically would require access to the whole, which you can not have.

(If you want to quibble with that list of primitives: Fine, just pretend I used your list instead. It won't change my point.)