Why did Spagnuolo stink as Saints' DC? (merged)

IMHO Spags is a crap D-Coordinator even with the Chiefs. Its masked by the fact theirs not many good offensive teams in the AFC,
Even after Mahomes (who is on their team) it could be argued that the next seven best QBs are in the AFC. Burrow, LJax, Allen are three for sure, then Stroud, Tua, Lawrence, and Herbert could all be in the mix before even mentioning Prescott, Hurts, and Purdy in the NFC.
but to Spags credit, the Defense has a habit of standing up against good offenses at certain points through the year or playoffs. Theirs also a huge degree of luck in Spags defenses where their is a couple star players that carries those defenses much how Tom Brady was carrying offenses. Most everything in NY was ran through Tom Couglin regardless Spags there or not, similar to how everything runs through Andy Reid regardless if Spags is there or not, its also now Eric Binenemy hasnt gotten a HC job, his departure from KC changed nothing.
I’m not sure what most of this even means, but standing up to good offenses doesn’t happen by accident