It has been stated otherwise. It simply says "Play it FIRST on XB1.." Even though you can play it on PC..and the 360.
EA won't do exclusives..Ever. Notice after they took over Bioware every ME game went Multiplatform? Included ME..Which people said would/could never be done.
EA making this exclusive would be like Ubisoft making AC or Watch_Dogs exclusive to PS4. At best this can be compared to Destiny. Activison and Bungie are working with Sony..The PS4 is going to get exclusive stuff that the X1 won't. X1 will get this first..and maybe maps will land on it first..Whoopdee do.
I fully believe exclusive games (unless it's 343, Naught Dog, SSM, etc) are going to go the way of the Dinosaurs this gen. There's no big money in it.