[rartichoke]

For some reason your "I had taken an hour out of my day" comment really bothers me.

The guy you interviewed probably spent ~4 hours preparing for the interview and then all of the time in the actual interview.

Let's say he takes 7 hours out of his life to interview for your place. The least he deserves is a legit reason why he was declined because your company still benefits from not hiring him. You get to refine your interview process based on real feedback.

The interviewee's time is just as valuable as yours. A wall of text complaint sounds pretty good. There's probably a lot of good feedback in there unless it happened to be filled with insults and other garbage in which case you should have been able to figure this out quickly and then not replied.

[stronglikedan]

If you give a reason, there's a small chance that you may have to defend that reason legally. Therefore, it's best to not give a specific reason. It's harsh, but protection of the business is more of a priority than potentially hurting someone's feelings by not giving a reason.