That's the problem - he doesn't. He's been all "cool" about everything this year, when on the track, other than 2 races, he's been very poor. It's the opposite to how he was early last year when he was building the reputation he's eroding now. He didn't want to talk to the media (understandably, though he's no kid) and just went out and did the business. Now he's expected to do the team and sponsor stuff, he can't fall back on the performances because he keeps making potentially race-ending mistakes, so he's having to mouth off.
He's trying to be Senna and falling short. Senna had an immense talent for grabbing his far inferior car and dragging it into positions you'd simply drop your jaw at. Hamilton's trying to do that this year when Ferrari's had the advantage, and he's just making mistakes under that pressure. He's built up this wonderful reputation and standard, and he's unable to match it.
If he wants the title he needs to sit back and rack up the points, not to try to win everything. He could so easily have lost his nose in Magny-Cours on lap 1, lost it in turn 1 in Silverstone, knocked himself out of the race in Monaco. He did knock himself out of the running in Bahrain and Montreal (though that was a different sort of cockup). Kimi didn't win the title last year by trying to go out and get the win everywhere - he just maximised what he realistically could. If Hamilton's here to entertain in the way Jean Alesi ended up doing, then that's fine. If he wants the title, he's still got a heck of a lot of learning to do.