FWIW - The Census data are for highest education level attained. So the population with graduate degrees are in addition to those with a bachelor’s degree. The percentage of those with a graduate degree out of those with a bachelors or higher is 36%, not two-thirds.
Back to the topic at hand, St. John’s has a clear educational mission and academic framework. They pull in a small subset of students around the 90th percentile, rather than the 99th. Is it possible to have a strong foundation in the humanities without learning rudimentary ancient Greek? Columbia and Chicago would certainly say yes. Brown would probably disagree about the need to require all college students to take the same classes like high school. Most academic faculty would probably also say it is a disservice to students to have almost no women or people of color in their canon. But, given a choice between academically dubious vocational majors and a St. John’s curriculum, the choice is pretty easy.