I'm sure that most US elite universities (maybe not Stanford) have a goodly number of undistinguished legacy students and humanities-focused undergraduates who "hate math". They're just dealt with through the aforementioned armies of TAs, the drift into easier or less mathematical majors, and of course grade inflation before they'd start to bother someone at Thrun's level. A TA or associate professor at an elite university might have a much clearer view of what undergraduates everywhere are like than Thrun.