I think there's a wider issue surrounding people who achieve a public platform for quite legitimate purposes who then choose to spout about matters way beyond their purview. I mean, the sort of thing that I spout about down the pub or when I'm shouting back at the telly, only they are doing it from a platform they obtained by means unrelated to the subject their pontificating. The Archbishop of Canterbury sounding off about banks (or, indeed, all those bishops in the Lords) or Prince Big-Ears burbling on about architecture, sort of thing. "Film stars" and "pop stars" seem particularly prone to appointing themselves gurus of this, that or the other, with the connivance of the media, of course.