This is because all kindles in mainland Europe all have
(edit) AT&T SIMs in them. It costs Amazon SIGNIFICANTLY more for you to use whispernet, because you are constantly roaming. The reason you pay the tax if you buy it on something other than the kindle itself is because at some point you could sync it on to your kindle, though archived items.
Sure, except that even Kindles that are wi-fi only had to pay the extra $2, not to mention those reading only on the PC or mobile app. It was a stupid system, but as I said, they are fortunately phasing the whole thing out now, and many books already have pricing parity (well, excluding VAT, but that's not Amazon's fault).
