George says: College economics is confusing because it's all wrong. The reason they still teach it is that these guys studied too hard to learn these wrong stuff, so they want to defend it and pass it to others.
(A) Many college graduates who have taken economics go on to successful careers in a variety of other fields.
Irrelevant. Their successfulness may have nothing to do with whether their have learned anything wrong in college.
(B) College students who major in economics tend to earn higher grades in economics than in their other subjects.
Maybe it's because economics is easy. Or maybe they have studied it very hard. Not threatening to George's line of reasoning.
Keep on asking, and it will be given you;
keep on seeking, and you will find;
keep on knocking, and it will be opened to you.