The Russian government is doing this so it can spy on itself ...
This is Russia you are talking about. The country which historically has been more institutionally paranoid than any other, not always without justification.
But yes, their primary motivation will be to stop Redmond and the USA government from spying on the Russian government. It's obviously become too hard for them to work out what Windows is up to, for them to continue using it as a channel for dis-informing Washington.