Vivendi published earlier versions, but after the split, Valve used Microsoft to publish the XBox version of the game.
Of course this could be JT getting it backwards and talking about MS windows as a platform rather than MS games as a publisher.
Its also likely that JT is going after MS because he has (yesterday I believe) settled with Take Two out of court and is now severely limited in what he can do or say about take two, its products, or any of its subsidiaries.