You want to know why? Here is why:
Same hardware but 100 Euro more expansive. Further, Dell recommends Windows 8, on the Linux shop page:
Fools, you will buy Dell for expansive price, and advertise Dell. If you live in Canada or the U.S buy ZaReason or System76. If you live in Europe, there are many vendors that sell great laptops without windows. I highly recomend that you search Google for Clevo notebooks. Many resellers are decent enough to sell them to private customers without forcing them to purchase Windows.