I mean, I lost count of the number of times where he went to the presser after a loss and addressed some issue we had with our defense or special teams and yet refused to can Drayton and Barry until he was left with virtually no choice...it pretty much seems after just about every loss (or even the sloppy wins) there's some sort of issue where we hear "That's on me, we have to do better" or whatever and it's just words at this point. Maybe there are not too many specific single-play instances mentioned prior but I think you'll forgive my skepticism at this point. I like the guy alright at a coach, and wanting to take the heat off your players/coaches is an admirable quality to have, but at this point it's pretty much an "I'll believe it when I see it" kind of thing, given his track record of empty "Buck stops here" type of comments. It is what it is.
While I see your point, I also understand that sometimes a coaches job is to be the shield for their organization at pressers. People can ask very stupid or too general of questions and expect rock solid answers of "who, why, when, how and what for." Some of the coaches answers are going to protect other coaches, players, etc., some of their answers are going to protect team strategies and sometimes, they just don't have an answer. The bottom line with a HC is "Are you winning or losing games?" "Are your players performing up to expectations." How they get there or the bumps along the way can sometimes be maddening and great sound bites for reporters and fans, but in the grand scheme of things, don't matter. The Packers lost the game, but Nixon returning a ball out of the EZ is not what lost them that game.
In the grand scheme of things, Nixon and Bisaccia have been good assets for the Packers. So over focusing on the 1 decision in the EZ, during a game of 100's of decisions, is being overly critical and nitpicky IMO. If it was a mistake by a player or coach, it will be corrected. If it is a repeated mistake by the same people, other actions will happen.
Personally, I like the way MLF handles pressers. He's not a big BS'er, nor is he all rainbows and fuzzy kittens. He gives the info that he feels is necessary, has his players and coaches backs and gets back to work.