Anybody else noticed this center problem??

Half time in this Pistons vs Bulls game and it's driving me nuts that Duren and Stew are just fine with letting Vucevic take wide open threes. I know they lurk in the paint for rim protection but it seems like they both have a total lack of motivation for playing scoring centers straight up at the perimeter. The amount of threes or even mid ranges they allow centers to take makes the difference in games like these