It will not surprise you, that I don't agree.
I see McD as someone who has enough self confidence to try to hire the best defensive coordinator he possibly could. There is no way to know why Fangio did what he did.....but you can clearly see the defensive play calling frustrated many of our key players on defense. I don't buy into the narrative he doesn't pay attention to the defense, he hired the best in the business supposedly because he understands the importance of the defense and made Fangio the highest paid D-Coordinator in the league. The Fins removed all of the obstacles for Fangio to be successful and yet he couldn't connect with the players or use them effectively.....and I don't believe Fangio simply forgot how to coach, he clearly was just not personally invested in being in Miami. I think the fact that the Philly job was waiting for him and he took it without considering other offers is telling in this situation. It is also telling that a not 100% Fangio produced a pretty good product when everyone was healthy which speaks to his coaching ability
I don't think blaming McD for this makes much sense. In my view, he did what he should have done and Fangio holds the responsibility of his own failures.