The problem isn’t a principle of a computer science, but one of just safety.

I think you missed the point entirely.

You can focus all you want in artificial Ivory tower scenarios, such as a hypothetical ability to rewrite everything from scratch with the latest and greatest tech stacks. Back in the real world, that is a practical impossibility in virtually all scenarios, and a renowned project killer.

In addition, the point stressed in the article is that you can add memory safety features even to C programs.

Also, who said this is a principle of computer science?

Anyone who devotes any resource learning software engineering.

Here's a somewhat popular essay in the subject:

https://www.joelonsoftware.com/2000/04/06/things-you-should-never-do-part-i/