Putting aside the “software is so different nothing else compares” argument, what you’re talking about here is tool knowledge vs design knowledge. Your ability to think and solve problems like a designer has very little to do with the tools you know how to use. Those core concepts you lay out aren’t tied to a specific tool. You use your own tool knowledge combined with your design knowledge to do design. Why shouldn’t we treat coding as just another tool we combine our design knowledge with to solve problems?
I believe 10000% that designers should be focusing on the core concepts of design you have lay out. That’s what I mean when I say “Code like a designer.” I know from experience there is no reason those core design concepts can’t be focused on while using any number of tools, including computer programming languages. Coding is just a tool, you don’t have to write computer programs the way software engineers do to get value out of them. The idea that you have to master both design and software engineering is false. If the goal of designers picking up programming is to be equivalent to a software engineer, they’re missing the point.