I'll assume you mean in general, rather than BU specifically. So, I would have to say that I think there is nothing wrong with that at all. It's a definite opportunity to gain some insight. I interviewed for a job last month and made it to the short list. When I got the call that I did not get it, I asked if there was anything I could do to improve for future jobs (including interview style or credentials). He told me things about my application that he loved and where I fell short. Of course, no one is ever obligated to tell you anything, but if they do then it is extremely helpful, as in my case. It's unfortunate that you got such a unsympathetic and almost callous (it sounds) response from your POI at BU. But, I would brush it off move forward. As others have said, it IS beneficial that he was blunt and you won't have to waste valuable time or money applying again.