I'll bet he did over his lifetime, just not in his specific choice of work. The things is, we may never use many of the things we learned in school, but the point of an education wasn't to remember everything you learned, it was to build a foundation of knowledge for you to continue to build on.
How many people today are scammed into believing things that are untrue simply because they don't have the educational foundation to question dubious things? Carbon dioxide is bad, mmkay? No. Carbon dioxide is life. Carbon is life. There is male, there is female, and there are abnormalities of both, but they're still base male or female. Child molesters in church or the Boy Scouts are bad, but groomers in schools are good. It's all in how the foundation is laid.
He may have been exaggerating a bit. ;)