Most of them related to how good the SEC is.
My "casual fan take" is in line with what IndyCoug shows: SEC got their corrupt little weasely fingers in the NCAA and jimmied the system to get 14 teams in, probably 10 of which were undeserving.
Saying many of those SEC teams that lost were underseeds is missing the point of the post. They shouldn't have been in the bracket period. 14 teams is ridiculous, especially when the previous record is 11. Of course to squeak in some of those teams, you have to give them lower seeds. I'd have expected a higher percentage of lower seeds to succeed than what the SEC has had.
SEC is corrupt. If utes didn't suck more, I'd say they'd be a perfect fit.