Arcade Fire hit the scene as part of the massive cultural shift toward all things indie in the early 00's. Oddly enough, the very term "indie" has undergone a major shift since that time. Indie used to refer to bands on small time independent labels, but now it's basically the new "alternative." If it isn't straightforward rock, and if it gets a little experimental, it's indie regardless whether or not it takes place on a major label. Arcade Fire is part of the major label indie crowd (distributed by EMI), but this EP is good enough that semantics really don't matter.
Just give "No Cars Go" a listen and I'm sure you'll soon agree that Arcade Fire is one of the best things going in indie, major label or no.