Isn't a contradiction to say that uncritically listening to a groups ideas doesn't stimulate creativity and then to follow that up by saying that listening to other people's ideas, even very wrong ones, increases creativity?
The way I read it, it's more of a social interaction phenomenon than whether ideas are inherently good or bad.
Something about knowing that people in the group disagree with some idea that's presented, and the reasons why they disagree, might be more important for improving your creativity than your own isolated assessment that an idea you heard is wrong.
