What Microsoft did for the Russian secret service was make the Windows source code available under a special NDA. Read the article you linked to, don't just post the headline.
Look up the term "open source" (generally an adjective, sometimes used as a noun), and specifically the verb usage "open source" (to make a body of software available as open source).
Open source software — software whose source code is published and made available to the public, enabling anyone to copy, modify and redistribute the source code without paying royalties or fees. (Wikipedia)Maybe instead of "has open sourced the code", you meant to say, "has made the source code available under NDA", which would be correct.
In no way whatsoever has Microsoft ever made the body of code known as "Windows" available as "open source", nor do they have any intention of ever doing so. They have made the source code available under NDA to various governments and agencies, including the Red Chinese and the Russians. They have made tiny portions of it publicly readable for the sake of encouraging compatible use of Windows APIs, but not for modification.