Because you couldn't answer a simple question, lol. I never said that MS isn't at fault, I just suggested that its easier to blame someone when you don't have the full details.
See, this is why that's a oddly specific request.
We have examples of games where cross-play is available between PS4 and PC but not Xbox.
We have examples of games where cross-play is available between PS4 and other consoles but not Xbox.
We have examples of games where cross-play was supposed to be a feature, but it was block by Microsoft and only Microsoft.
We have examples of games with cross-play on Xbox, but they're all limited to older titles when Microsoft made expressed exceptions or to games exclusive to the Windows App Store.
We have multiple developers confirming that Microsoft, and only Microsoft, doesn't allow cross-play outside their platform (Xbox and Windows Store).
Yet you are still demanding we find a title that was only released on Xbox and PS and not any other platforms, and has multiplayer, and considered cross-play functionality, and have proof it was blocked by Microsoft. That's fishing for confirmation bias.
If you told me you were Major Nelson's second account, I would believe you.