[Someone]

And, likely, some good computer scientists would be lost to the world. You should also ask them why they want to learn programming. Many of them will answer they want to become programmers, while they do not have a clear picture of what that entails (it is not code writing all the time, most programmers do not write games in languages they chose, a lot, despite the fact that it is a job where all workers can automate repetitive jobs, a lot of the work is repetitive, etc)

Maybe, once they realize what is the difference between programming and computer science, they prefer computer science. Problem is you cannot learn them the difference in a few weeks; it takes years to sink in.

So, what do you let them do in the mean time? Waiting is a waste of the years in which learning is easiest for them. So, do we let some grown-up decide who likely will make a good computer scientist, or do we let many more start on that trajectory and see how far they get?

I think the latter is the better choice, if we also provide smooth ways to move from one to he other.

[slightly related: I once read a teacher in a nursing school state: "when they come in, all the boys want to ride an ambulance, and all the girls want to work with kids. We have to work a bit on that in the first year"]