Yeah, as someone who's been involved in making hiring decisions, the type of transparency you're looking for wouldn't work. "Not a good fit" is an excellent reason in many cases to make a decision, which comes down to what you're able to glean about someone's personality from a half hour of asking them questions.
To substantiate, I will take personality over experience or other hard qualifications any fucking day. I've hired two people that were 100% my decision, and both of them became central pillars of the office - a couple of the most dependable and pleasant to work with individuals we have. In both cases, the decision came down to my impression of what their work ethic was like, based on the thought processes I could see through their stories about past work experience, and my impression of what their personality would contribute to the office atmosphere. On the other hand, I've had people report to me who were hired by other managers and had excellent qualifications on paper, but were bitter, hateful human beings who knew how to play shitty games to make everyone around them miserable and unproductive in ways that couldn't easily be measured and pinned on them directly. I've also seen, recently even, people who have worked with a candidate in the past tell managers "don't hire them they're bad news" and managers go ahead and hire them anyway because they're the most qualified... and then 2 months later, fire them and start over again because they really did turn out to be shitty people who had managed to build up a good resume.
But if these decisions were being scrutinized by 3rd parties, I probably couldn't have made them. It's hard enough already. Everybody hates making hiring decisions. I felt for every applicant I didn't choose to hire. If I knew I could face potential interrogation by someone other than my co-management about "Why did you pass up this qualified applicant for this inexperienced person", it would seriously damage my resolve to pick the candidate who I honestly thought was the best choice based on anything but hard criteria. And if the basis of my decisions was made to everybody I didn't hire, it could have awful consequences for my career later on. Especially when based on soft criteria and unsubstantiated suspicions about personality issues someone would bring into the office, if I was forced to pass that back to them as cause for rejection, that would unavoidably be taken personally and I would expect vengeful behavior if I ever became their co-worker or was interviewed by them later on. My wife recently became friendly co-workers with someone I interviewed in the past and didn't hire, and I had to hang out with him for a bit at her office Christmas party. Because all he got was a flat answer, it was an amiable interaction. He learned some things after the rejection that made him thankful he didn't get the position anyway, and there were no hard feelings. Wouldn't have been so if he was told that I didn't hire him because I couldn't tell if his personality was really that bland and he really had so little to say about his past experiences in office environments, or if he was hiding that he was secretly a conniving team wrecker.