I ask because elsewhere on this thread you have people bitching that they were asked some low level CS questions about inverting binary trees and the like, and how insulting they found that.
While I sympathize, it's not going to change the fact that the company does want to hire engineers that are equally competent at contributing to some sexy new high-scale AWS services as some boring business reporting features. Google, Facebook, and Microsoft all do exactly the same thing.
On the other hand, if you had people that were actively rude, did not give you hints when you got stuck, and made you feel unwelcome, that would definitely warrant feedback. Though, as you said, it's too late since it's 2013.
I advise anyone in the future who runs into this kind of situation to contact your recruiter with feedback, and be very clear if you had a bad experience. Amazon takes customer feedback super seriously, and when we interview, the candidates are customers.