You can't blame the users though. If I have a bad delivery experience, I'm going to leave a bad review. It's Amazon's problem that they don't let you differentiate between product issues and delivery issues.
Oh yeah, I'm definitely blaming Amazon, they should let the user categorize their complaints.
And I'm going to mark it 'unhelpful', because I don't care about your bad delivery experience. The only people who need to hear about your bad delivery experience work for Amazon customer support.