Why haven't defenders learned? Don't try to tackle Marshawn Lynch. It ends in sorrow and physical pain. Your best bet is to offer him large amounts of skittles for agreeing to take a knee after only a six or seven yard gain.
Darnell Dockett did not use that method of bargaining. Marshawn Lynch hurt him:
It's like the reverse of the Jadeveon Clowney GIF: the running back decapitating the dreaded, red-wearing defender and continuing with his life like he didn't even notice it happened.