Yes, 360 and PC are both platforms operated by Microsoft. Since Sony is making this game, yet it is available on Microsoft Windows, why would they not go one step further and port the game to 360?
Also, Microsoft's game coding is extremely similar for PC and 360, PS3's is quite different. So if Microsoft has gone to the trouble to code it for PC but you can't understand that they should do the same for 360, there is no help for you.