It's sports. Things happen. I still remember some big sportswriter in 1983 saying that it was absolutely impossible for NC State to win the championship, when they were at the Final Four. And then the Wolfpack won it.
Sure, the odds are usually for the higher seed. But Ess happens. That's why you try to get into the tournament. Not tank and say "we are building for a Super Bowl, not one and done." You get your *** in the tournament and try like Hell, Carousel.
I also remember a (relatively) recent Giants Super Bowl win when the fans were bemoaning that they had snuck into the postseason, didn't belong there, and were hurting their draft picks. Then they won it all!
Anyhow, you can't generalize off some random single occurrence statistic. There is an incredible amount of p-hacking going on with how people use stats in sports now. Only rookie to win 4 games with more than 260 yards, in a year divisible by four, with games in the Eastern/Central time zones. And junk like that. You can make almost any inference you want with that amount of post hoc interpretation.
Who the *** cares if MM lost a playoff game? 12-5 is a good record. Well above the average performance...and every single team is trying to win and be above .500. But (in general), only half will do so.