C'mon! One week away from a primary that has filled the news for the past year and 31% still can't make up their mind?! What's up with that?!
That's actually pretty common. You have to remember that the vast majority of people don't pay attention to politics with the same intensity that members of this site do. So what they see and hear between now and the 15th will have a significant impact on their vote. They won't take time to research the candidates at this point - they will go with how they "feel" about them, based on the news and advertising they are exposed to between now and then.