Again, like I said in the comment that this parent comment replied to: provide a waiver that basically says the candidate can't use the feedback legally. It's a similar thing with the NDA on the reverse end.
Firstly, NDAs and waivers are not bulletproof and may not hold up in court. And even with a rock-solid NDA guaranteeing a victory, going into a courtroom is not a desirable situation for any person who isn't being paid to be there.
Like I asked in the comment replying to your previous one: what benefit does this give the business whatsoever? This will cost money, time, and very possibly headaches (whether reputational or legal), and for no benefit to the business. Why would they consider this?
Common courtesy? Same with being nice and polite, saying hello/goodbye, etc. It wastes time because you could get to the point faster but it’s nicer and makes the interaction more pleasant. That’s it. No other reason. Just make the world a slightly better place with a tiny action.
Like I asked in the comment replying to your previous one: what benefit does this give the business whatsoever? This will cost money, time, and very possibly headaches (whether reputational or legal), and for no benefit to the business. Why would they consider this?