Amazon Technical Program Manager interview questions

Applied online for one job and was passed through several recruiters and several phone screens. Onsite was set up from the last phone call after filling out a list of questions. A recruiter will call and detail how the onsite will go, and your travel will be planned out. They pick up the tab. It is as grueling as advertised, where you are interviewing with 5-8 people over a six hour period. The questions were not difficult if you know your stuff, but the day is a very long one. Lunch is a nice reprieve as you are assigned a lunch buddy. You can discuss work, but we discussed favorite travel places. Everyone was nice, gracious and made me feel welcome. I stumbled a question at the end of the day but felt really great about the interview and the team. I got an email from the recruiter saying they would debrief and be in touch within a week as they pride themselves on being fast. I got an email to set up a call 24 hours after the debrief; was rather surprised when told they would not be proceeding with me as a candidate. They are not allowed to give feedback at all, but internal applicants were mentioned in passing. I was told to feel free to apply for any other jobs that interested me. Not sure I will, though. The negative: I burned 3 vacation days which would have been bought back when my current company shuts it doors. That is around 800 dollars lost, and that will not be reimbursed. I do think that any interview that does not end with an offer is a waste of time, especially without feedback as to why....however in a litigious society, feedback is verboten.