This sounds like a huge self-rationalization to me. While there have been great leaders who don't know how to code, comparing it to a designer knowing how to mix cement is a terrible analogy. Coding is a fundamental skill in the 21st century, like writing or being able to do basic arithmetic. It's not like asking a designer to rivet girders, it's like expecting a designer to know geometry. Coding is simply a bunch of logical constructs expressed in a way that can be translated into machine code.

Imagine hiring a CTO that didn't know how to read and write. In the 21st century, where almost every aspect our lives is dependent on computers, having some knowledge of software engineering should be considered a basic skill.