The whole thing is designed to put people off and make it difficult to get problems resolved.
I'm fairly good at being annoyed enough to work around this but most people out there can't handle things like that easily and Amazon knows it.
Last November, my Logitech mouse's scroll wheel started acting funny. Tried to check on Amazon the warranty situation, the docs said: take it up with the manufacturer (note: the mouse was sold by Amazon, wasn't a marketplace item). This was like two weeks before the 2-year warranty was up.
So, I headed on over to Logitech. Man, their site sucks. My mouse was a "gaming" model, so it wasn't directly clear where I should seek help. I end up with some support guy who was obviously doing something else in parallel, judging by the time between replies. Went through the usual checklist (is it on / did you try unplugging and plugging it back again?). Never mind that before getting on the chat, I had to fill up a form with the exact same questions, up to and including the serial number, which is the first thing the chat person asked for. Half an hour later, he asked the killer question: where did you buy it? Amazon. Oh, take it up with them, then.
Went back to Amazon, opened a new "other" case. Less than two minutes later, I was on the phone with someone from Amazon, asking me point-blank whether I wanted them to try to fix it or reimburse me. Said the latter, and he asked me to be sure to send it within 30 days.
Guess where I bought my next Logitech mouse?
So yeah, Amazon's retail support experience is still top-notch in my book, at least on this side of the pond. This was for an account without prime support that doesn't do a lot of business with them.
I'm a "high hitter" customer. I have prime and spend a hell of a lot of money with amazon every year so they tend to do what you ask eventually. But if you're a new customer or low value one your customer experience will be very very different. I know several people buying 1-5 things a year who have been told to piss off.
It's just a coincidence that when it comes to retail, the cheap option (just ship another one out) also works well for the customer. At scale, shipping duplicate items, even expensive ones still works out cheaper than well-trained, competent, well-treated and well-paid humans.
This one on the other hand requires engineering time (can't be resolved by a bot or monkey pressing a "ship another item" button) which isn't cheap and unless they have legal liability, it's cheaper to just stonewall or even ban this customer forever and lose their business.
