That wasn’t phrased exactly right; the point is that those who benefit from formal education are those generally motivated to seek knowledge on their own. (Similar: it doesn’t matter what parenting book you read, the fact that you wanted to be a better parent makes you a good parent.)

Throwing masses of disinterested students through 4 years of classes doesn’t benefit them the way everyone hopes.

A doctor is not "educated" in the classic sense. He learns a trade -- but that is not "education."

The GP is correct; and your view of education is a good example of it.