Maybe it’s CS2 that’s wrong, not just CS1
I don’t disagree with the claim here, that students don’t learn to program that well in one semester of CS. But I think the author doesn’t also consider that maybe our expectations are too high in CS2, too. Programming isn’t learned quickly. If we don’t have it in high schools, most people are going to take multiple semesters in undergrad to become competent — for expertise, multiple years.
In particular, I believe that expecting a student to learn to program well enough to study Computer Science in a single 15-week course is almost as absurd as expecting a student with no instrumental musical experience to be ready to join the university orchestra after 15 weeks. There are, of course, musical prodigies that can handle this challenge. Likewise, there are many “natural born programmers” who learn how to program with very little apparent effort. However, these individuals are the exception, not the rule.