They have paid for the right to transmit the content. They may not own it, but they have paid for it, and so therefore, can provide it the way customers want.... at least, until the content kings engage in anti-trust action to stop them.
What I suspect will happen is when the agreements come up for re-negotiating they will attempt to punish Dish and force them to disable this feature. Dish has handed themselves a protracted and expensive legal battle, but if they win it, then it will be of benefit for consumers everywhere. Go Dish.