Seriously, unsportsmanlike conduct is a violation of the Xbox Live Code of Conduct is the reason. Because of wrecking other players attempting to enjoy the game as intended.
Neither bans nor the enforcement of the regulations by Turn 10 employees are discussed on these forums. You may send an email to firstname.lastname@example.org if you wish, but will probably not receive a response prior to your initial seven-day (168-hour) ban expiring. If you write, I suggest you leave the attitude out.