The other issue is the concept of "free software". No matter the claims, when the term free is applied to a product (or product class) like software, the immediate implication that the price is free. The "free as in free speech" doesn't work too well because speech is not a product. Also, Windows doesn't exactly stop me from doing questionable activities, like authoring documents that would be considered subversive.
Telling people that Windows takes away their right to view and modify the source code will at best give lukewarm response, because most people have other concerns.
