Yes, of course, brilliant move. I spend about $1000 a year on books from Amazon for my Kindle. I might spend $7.00 at a non-Amazon source, and only then because I can't find a particular book at Amazon. So, of course it makes perfect sense to drive me away as a customer because I spent that piddling amount at another store. Amazon clearly does not want the money that I was previously spending in their store. At least I hope they won't miss my money, I'm simply going to switch my reading to Public Domain and non-DRM'd sources, and Amazon can find another chump to purchase their products in the future.
You are right, that is a poor analogy. A better one would be a consumer purchasing a television set and then being told that he/she can only watch television shows on which that manufacturer advertises, or can only watch stations that pay the manufacturer a license fee. Amazon is using DRM to force people who purchase a Kindle from only obtaining content from them. Thus, they dictate what books the user can or cannot read on the device, regardless of the fact that the user has paid for a digital book, unless they have paid Amazon, they may not read the book on the device.