You do realize that the person you're replying to is not making a value judgement and probably agrees with you.

If you have two groups of people, one with a low but nonzero signal that they can do something, the other with no signals, is it still a good idea to use that signal?

You'll get fewer bad employees, but you also discard many capable people who haven't had the opportunity to even try for your signal.

It still is a signal, albeit a weak and highly inequitably distributed one.