They are especially scared to give negative feedback to candidates out of fear that it might be misinterpreted as discrimination.
And this is why we can't have nice things.
And this is why we can't have nice things.
I think the opposite is true; when given no concrete feedback, one begins to hypothesize why they were rejected, and their mind will often point them to discrimination as the reason.
If one is given clear, concrete feedback ("We rejected you because you didn't come up with a simpler algorithm, and you lack experience with framework x"), there is little room for them to think they were discriminated against in any way but their skills/experience.
Or even more likely, someone will inadvertly show his bias that could have stayed under cover. People are not that great in hiding their biases over many interactions.
If they were confident about having processes with no discrimination, it would likely be advantageous to the company to show their cards and give the feedback.