Idk, I played a lot of football when I was younger and a lot of the more closely-called stuff is easy - sideline collisions, late hits vs the whistle, PI on both sides......but the defender vs an oncoming QB is not one of them. You're expecting a guy to just blindly predict if the QB is going to slide or not, duck his head or not, etc.
It can't be done. You either guess right or you go against all previous coaching you've gotten. Football can be made more safe, but it can't be made totally safe. This effort to make it totally safe is silly.