No goalkeeper in the league, bar maybe Courtois, would have attempted to catch that ball under pressure. Besides that Robles punches the ball more than Howard it's one of the reasons most people were concerned about him coming into the team because his punching is so erratic.
Martinez was always going to reinstate Howard when he was fit, he's clearly his number 1 goalkeeper who has his faith because he's a better goalkeeper than Robles. If this decision has altered your opinion of Martinez I'd imagine you had been wavering before it was made because it was the clear and obvious decision that every other manager would have done.