You are absolutely correct. That was a mindbender for me, and is causing me to rethink how I see the D. This is worthy of a new thread.
I do think this board sometimes, when it talks about coaching, has a complete disconnect with the fundamental issue: ultimately, the coach is not on the field, only the players are. Players persistently and frequently break from how they were coached -- even players who play for a very strong coach. Every player has a certain level of "coachability." The notion we seem to have -- that a player who doesn't "listen" to his coach immediately will be taken to the woodshed or cut simply doesn't work that way. Sure, there are some circumstances where blatently ignoring the coach will get you in the dog house. If the coach calls blitz, and you don't, you're in trouble. But football is way more nuanced than that.
Football -- like every sport I guess but more so -- is ultimately a game of deception. Defensive players must be reactive. You want a player to be coachable, but I don't think even the most seasoned and excellent defensive coach wants any defensive player to be a slave to coaching. It's a balance. You tell a player to stand in a certain place during a certain play, but you also want him to be able to read when the play is changing and not to continue standing there when he could make a play. At the same time, you don't want a player, in the name of "reaction" to leave his post and give up a play.
Offense is much more rigid with respect to coaching. Playing defense is way different. Coaching is about preparation and playing is about execution. A good coach puts the player in the right position and teaches him to react or what to expect, and also has a much more significant sense of what the other 10 players are doing, so the player can't just be a free agent. But it's a shared responsibility, and the bottom line is that players need a decent leash. Sometimes, like in the video, they decide what they are going to do. It happens all the time, and the coach has to walk a very fine line between demanding rigid adherence and letting the player be reactive, which BB seems to do pretty well.