I think it can only be fair to ask for feedback from a rejected candidate if you (the potential employer) are willing to give feedback yourself, which is rarely the case, especially from larger companies.
This might be what you'd think intuitively. I've conducted ~500 technical interviews, and in my experience candidates who are obvious DNP (do not pursue) often times really do not want your feedback or do not care about it, either because they think they're smarter than the whole process, or they're too busy turning inward to deal with an emotional breakdown. But those very candidates are the ones who are likely to leave the feedback!
tl;dr candidates are happy to give feedback whether or not you provide any yourself.
EDIT: I agree with you though. An interviewer should be ready and willing to provide feedback if the candidate signals that it would be welcome.
> An interviewer should be ready and willing to provide feedback if the candidate signals that it would be welcome.
And at which point would this happen, I wonder? All the interviews I went through during the last 4 months didn't have one person sound inviting along the lines of "we won't take you but if you think we can improve our process do let us know". Not one even hinted at that. It's all very... impersonal, cold and often feels like copy-pasted emails are being to sent to the candidate.
You are kind of assuming -- way too generously -- that the process and the interviewers are actually open to feedback. Most people, including in tech companies, are happy to tick boxes and check in / check out at given times of the day, and do nothing else more creative or requiring special attention (like recruiting).
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EDIT: I tried giving feedback -- unsolicited -- after the rejection in my first 5-6 interviews. Didn't go well. You could tell people got offended by very simple points like "would have helped if you told me you will measure me with one extremely specific test while I am looking for a generalist role" or "what was the value of imposing a hard deadline on a homework while the candidate is going through several interview processes in parallel? does that tell you anything about their real productivity?", and a few others like "I am not sure that teling me 'I am not like the others in the team' is a valid point in remote working conditions where comms are mostly async and people don't chat that much". Etc.
In the end you get tired hitting a brick wall. People are generally not receptive to feedback and even react in a hostile fashion when it is given to them. Plus when you want to go through 35-50 interviews, at some point you really start counting the hours that each company is taking away from you before rejection and you figure it's not worth it to try and present feedback where it's clearly not wanted.
Sorry to hear about your experiences. It sounds frustrating.
I think there's some miscommunication happening here. The line you quoted is specifically regarding the person conducting the interview looking for signals to provide feedback to the person being interviewed, not the other way around.
I would not recommend providing feedback to your interviewer unless they explicitly ask for it. It's likely to just become a clash of egos, and if the company is larger then it's likely the interviewer doesn't even have much power over the process anyway. If you're being interviewed and hate their process and/or the way they communicate, the best thing you can do is politely inform them it is not a good fit, remove them from your list, and move on.
Oops, I guess I misread indeed. And you are quite right on your last paragraph -- found it the hard way.
I also agree that the interviewer shouldn't just give feedback without asking because I know many interviewees will react badly.
It's just that in my case no feedback was wanted in either direction. And job-hunting is a game of numbers and evolution (okay, most of the time, definitely not always): you seek to adapt to the current conditions and see what you can improve upon for the next interview. Some feedback would have made your time and effort worth it. Giving you zero feedback wastes your time entirely though.
tl;dr candidates are happy to give feedback whether or not you provide any yourself.
EDIT: I agree with you though. An interviewer should be ready and willing to provide feedback if the candidate signals that it would be welcome.