Maybe. There are certainly people in all fields who are book smart and did well in classes but are useless at actually practicing their field (not to mention people who cheated in school and got away with it and aren't even that), and it is worth filtering them out. But I think it is weird that CS expects good workers to have these passion projects. Do we expect civil engineers to build bridges in their back yard on the weekends? Can't someone just be good at their job and have other interests outside it?