Crafting strategy?

I was reminded by a recent conference of the one-time popularity of the idea that strategy is ‘crafted’ by leaders, rather than planned [we can thank Henry Mintzberg for that one]. But there’s a puzzle in all this. Henry and friends got this idea by watching and talking with management about how strategy actually develops. My problem is this – just because that is how strategy is done in practice, why on earth do they think that’s how it should best be done?