It is not a technicality; it is a way of legally doing it. I see your point though; buying is, with the added burden of patents and copyright on top, a wrong term. You cannot buy anything in the sense we would like to buy it.
Whether it's legal or not to prevent you from running the software you want and the software you write on your xbox, IMO it _oughta_ be illegal, whether they just say you are leasing it or not.
