I'm not especially surprised by this move. Since the rise of the DVD, Sony has basically dominated all forms of circular disc-based media and it's various deviations (including Netflix or at least it's physical content), so using their brand licensing to essentially blacklist their competition from receiving their content is, actually, pretty damn clever. Sure, it comes off as a bit of a dick move and as a little underhanded, but it is a pretty smart tactical move.
For the life of me, I can't think of any feasible or practical retaliation along these lines that Microsoft can fire back that them. Sony mainly deals with media and devices that can play it, so Microsoft can't really reach out and touch them on their turf, or at least not easily. So, if anyone has a suggestion for Microsoft's retaliation that is possible, realistic, and of course legal, feel free to chime in.