> I don't understand why do you want to have a special case for Linux. 
> sys.platform is already different for each major version of:

That's because Linux uses major version numbers in an entirely different
way than these systems. There is a traditional usage of major versions
(to indicate significant changes), and the systems you list follow this
practice. And then there are systems that break with that tradition, and
use the major version for marketing and other purposes, and Linux is one
of them.