I agree completely.
" Programming is a deep technical skill, just like many others, and the way you hire for those types of positions if you don't understand them is to rely on the judgment of others who do."
Exactly! This is the central point. This is how I (as a programmer) would find a good lawyer or doctor or helicopter pilot from large numbes of doctors or lawyers or pilots with similair sounding degrees and other "indicators", for example.
I am just not convinced of the whole idea of using "indicators" as a substitute for the above. It is not so much that any indicators are wrong in themselves , but that unless I have someone who knows how to use those indicators correctly.
Now I don't know anyone who can help me with the judging , I could go with a list of "common sense" indicators and take my chances. I have serious doubts on how much this will succeed in picking an exceptional doctor/lawyer/pilot etc.
You can also intuit something about someone's technical skills by looking at the types of places they've worked for. Some guy who has hacked together fifty is likely not as technically skilled as someone who worked at Google and Facebook. That's not a full-proof test, obviously, but there isn't a full-proof test here, even if you are a programmer.