Yes you must be DUS to get into Smeal.
Weedout means there’s a set percentage of students who WILL be eliminated. In high school roughly, 40% get As, 40% B’s, the rest C, D, F. In weedout class where only the ’ high school A-B students’ are, half of them (so, even A students in high school) will get a B- or less. And since you need B to B+ in every class to get into Smeal, it means half the class will lose its chance at Smeal right there. So you must’ve prepared and you prepare by taking Calculus in high school before you take calc 110.