He would say that.
So hire Hamilton and prove it.
I wonder. Hamilton raced for McLaren under Ron Dennis, who was infamous for his disciplined approach to F1 racing. Hamilton then moved to Mercedes, and while Toto Wolff is no Ron Dennis, I think it's safe to say that the Mercedes team is the most disciplined group in F1 right now.
Would Hamilton do well in a team that 'brand focused' like Red Bull? Or the insane politics of Ferrari? (I actually do feel that Hamilton would be a good fit for Red Bull as a brand)
Certainly putting up with Dennis or Wolff takes a special driver too. I think it says a lot for Hamilton to maintain the sort of professionalism they look for, while still being the 'fun guy' he likes to position himself as off track.