Because you own your phone.You bought it out right. Rooting it just voids the factory warranty. Tethering, which in this case "illegally" since metro doesn't allow it and doesn't have a plan for it, is basically stealing. You're stealing more of their service then you are paying for. Yes you are paying for it every month FOR your phone. But not for your computer,Xbox,PS3, etc. Basically as I see it as it comes down to money. If Metro comes around, which I've heard rumors of them coming out with a tethering plan, and allows tethering under the circumstances of their terms of service, its fair game on the forum. BUT since they don't and it is basically illegal in a sense and since Android Forums doesn't allow "illegal" activity and or working over the "system" its not allowed on the forums.