True, but there's a heavy selection going on there. A packed complexity class might mean 50? enthusiastic undergrads out of several hundred math/cs students at a university.
A dedicated and charismatic professor might be instrumental in turning an interested computer science student into a raging algorithmist (indeed, I actually think a lot of computer science grad students study what they study because somebody appropriately passionate introduced it to them), but converting a just-here-for-the-requirement high schooler is a different story.