Why can’t 32 humans play QB in NFL at a high level?

This video is the biggest disappointment after reading the headline in a while.

It starts out promising that immediately whittles the number of people who could possibly play quarterback by removing people from other countries, etc, but then the logic stops making sense about how certain teams carry 2 mediocre QBs for example.

Why can’t 32 humans play QB in NFL at a high level?