Having said that, I do think not getting back to him at all (even if that was with an explicit rejection) is a complete fail.
Based on anecdotal data, it seems to be increasingly common for modern companies (though I usually hear about it on companies that are much smaller than Amazon, which should have its HR shit together) to just go completely incommunicado with someone once the decision has been made to not move forward. Doing this is completely unprofessional (no matter how big or small your company is), especially in the face of explicit queries about the status from the person who was interviewed, and I applaud the guy for naming and shaming Amazon on that aspect of it.
Fix your shit, Amazon HR/hiring managers. Don't be jerks.