https://www.quora.com/Why-dont-companies-give-interview-feed...
https://www.quora.com/Why-dont-companies-give-interview-feed...
I've found most of the time, unfortunately there's no good in giving details. I realize people genuinely want to improve, but most of the time the reasons we don't hire someone aren't actionable.
And, parent had a good point to. The one time I asked for feedback and received it, I did react the same way (Them: We didn't see this; Me: But I have done that!). I figured while I had their attention to give it a shot. I was already rejected so what's the worst that could happen? Anyway, I tried to be extremely thankful and polite about getting the feedback. Should've done the Glassdoor thing since they also actually formally rejected me and did so in a timely manner.
That top answer there leaves a lot to be desired. Suggesting that a candidate offers "no value" to a company if they are not hired is very short sighted.
But that's a fair point about waivers not being legally binding.