The story seems to be from leaked internal documents. Haven't we learned better over the past 2 months than trusting the "official statements" afterwards, that inevitably deny it whether it's true or not?
At the very least, I think this deserves more exploring. It's not the first time I saw the Germans weren't happy with Windows 8 and its "secure boot". This is from last November:
http://www.linuxbsdos.com/2012/11/21/german-govt-comes-out-a...
And it seems the source for that is your source. So are they contradicting themselves now?
http://www.bmi.bund.de/SharedDocs/Downloads/DE/Themen/OED_Ve...