Dude I couldn't imagine telling a hopeful young person that they didn't get the job. Do you tell them why, so hopefully they can take that info and grow from it, or do you make something up so they don't feel like shit?
Really? Is that a real thing? (I'm a tech recruiter in Chicago) If I recruit someone good I don't expect them to nail the first interview. Sometimes they do and that's great but more often then not it takes some fine tuning. I'm not going to give up on them after one interview.
Half of my job is helping developers with their soft skills. I see tons of guys who can do anything that's asked of them but they just cant interview well. Some people are really bad at telling interviewers what they want to hear, some people are bad at sounding excited about what they have been working on, and some people are really bad at talking to people they dont know.
After first round interviews I sit down with managers and ask specifically why they were a yes or a no. If he tells me it was a technical problem then I get as many specifics so the developer can fill in the gaps for the next interview. If it's a personality thing then I'll work with that developer so they can nail the next interview.
I've had maybe 2 managers ever be sheepish about telling me why a developer was a yes or a no.
In my experience, you have to separate 2 very different situations:
-- When I ask why I didn't got the job directly, I never get an answer. It only happened to me once, over a couple dozen interviews (I failed their silly test: debugging flow charts on paper). Even the companies who were polite enough to tell me of the rejection over email never replied when I asked why.
-- When someone else asks on my behalf (an acquaintance of the company, a recruiter, or whoever tried to sell my services when I work for a consulting company), they always get meaningful feedback.
If you're looking for a job, and keep getting rejected, try to go through recruiters. I've heard that constant pestering over the phone also works, but I never dared.
In my experience, Google for example were not willing to tell me why I didn't pass an interview some years ago. I don't know what their actual reason is & can only speculate.
I didn't experience it often but it did occasionally happen with other companies too (I have been working as a programmer for the past 14 years & worked/interviewed with many companies).
That's the fear, though. If you say "We didn't hire you because X", people might think "I have X! So clearly you are unlawfully discriminating, and if I can make the argument that I do have X, then you must be lying about why you didn't hire me."
Besides, people apparently do make hiring decisions based on things like "culture fit", which is a pretty good proxy for race, age, and social status anyway, so...