Terrible Marilyn Song sung by that British Lass

Why on earth did they use that god-awful song at the beginning, middle and end of this doco?! It lent a tacky, cheap and dodgy feel to a subject matter that is already hard to take seriously. Ironically, I have no doubt that Marilyn was murdered - by the mob, Bobby or the CIA - who knows....I just feel a more suitable track (despite the lyrics being relevant) or maybe none at all would have been more appropriate.