You would be extremely lucky to have someone talk to you about why they didn't hire. They have no incentive to talk to you and plenty of disincentives, for exam

You would be extremely lucky to have someone talk to you about why they didn't hire. They have no incentive to talk to you and plenty of disincentives, for example just not having the time. It might be HR policy to avoid contact for fear of leaking info that could lead to a lawsuit.