Look, I like McCourty. Jr and Sr (and honestly I have no idea which is which, as far as who is the eldest). Belichick likes him, he's been around for a while, and he's been solid. Just look at this beautiful interview, in which he peels back the curtain more than almost anyone on the NE staff, while not revealing a single gameplan element or violating the Patriot Way.
https://www.patriots.com/news/transcript-devin-mccourty-press-conference-10-18
He knows he messed up. He was asked about it, directly but indirectly, and referenced that it had been addressed. I trust that. Seriously, the guy has been a captain what, 6x since 2011? If you want to talk about bad, bad plays, there have been plenty of those to go around, in all three phases. The guy's locker room contributions, schematic knowledge, and assistance in getting the defense as a whole into the right spots can't be ignored or denied. And yes, I feel it too when the defense gives up 40+ to the Chiefs or the Eagles or whatever. I recognize that those with the most leadership take the most blame. But seriously, if you have a top 5 defensive player list and McCourty isn't on it you're being obtuse or disingenuous. Let's please not call for his head while the team has legitimate Super Bowl aspirations.