Microsoft has decided to push this if you want most apps from them.
With LibreOffice and Caliigra http://www.calligra-suite.org/ are you sure you need Office?
Bob
I purchased a copy of Office 2013 home&business. When I go to download the software it requires a Microsoft Account.
Why do I need to open an account with Microsoft to use software I bought and paid for?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic