You make my point for me; this is a company that has a long history of inordinately poor strategic and capital allocation decisions.
Don't stop just at shale and Gulf of Mexico blunders.... look up Beenup, HBI, Hartley Platinum, the acquisition of Billiton...the list of monumental stuff-ups is long and varied.
So why them selling out of a particular business today suddenly connotes astute strategic insight would be lost on any impartial observers who are appraised of the long-demonstrated ineptitude of BHP's strategic culture.