Jeff, FWIW I think the M6 or 6 series is just about as silly as the X6.
The M6 is just as heavy as the M5 and it's more expensive. But, would we start throwing out insults to the people we know who bought one?
No, not insults of course. But I agree, the M6 is silly too. After driving the previous generation I turned and said "It's a German Camaro. Big, heavy, powerful and ridiculously space inefficient." That said, doesn't the M6 have a lower of gravity than the M5? So in terms of its mission as a performance car, it is theoretically a superior handler to its cheaper stablemate.
I don't mean to insult or attack someone who lusts over an X6 either, I just want to understand how it's possible. So far all I've seen is a lot of people saying "Well, I sure don't like it either, but good for others for thinking it's swell." At best we could suggest its very polarizing styling is enough reason for those who like it to buy it. Fair enough. People throw away money on all sorts of things I don't understand.
I'll chock it up to the X6 being the equivalent of a hot pink, velour leisure suit. If it works for you, more power to ya, but it seems most of us wouldn't be caught dead in it.