Shooting 80 while in the lead at one major, you can chalk that up to youth and give him a pass. Do it twice, as he now has, and he is a choker. No doubt about it. It is now up to him to prove he is not a choker.
If he were older with more time on tour I'd agree with you. But you hit the nail on the head with his youth and inexperience when it comes to handling the pressure of a Masters weekend. He needs to have a long chat with Dustin Johnson...