No. This is false. It has nothing to do with opinion. Based on their fancystats you can calculate the chance each team would beat another team. You can then calculate how likely it is a team would go undefeated against any schedule, including Miami's. None of the bubble teams are likely to go undefeated against Miami's schedule.
Yes. You can do that. And ultimately what you'll learn is...
Going undefeated in a manner like this is total crapshoot luck. Yes, it's REALLY rare. I.e. I just did a quick calculation. 0.9 ^ 31 = 0.038.
You know what that means? If you're 90% likely to win every one of the 31 games in your regular schedule, you're only 3.8% likely to win them all.
It's not like they were just out there dominating everyone. Of those 31 games, 4 went to OT. Another 5 were won in regulation by one basket (4 games by 2 points, 1 game by 3 points). Meaning that as you got towards the end of each [close] game, the outcome was pretty close to a coin flip. The fact that all 9 of them were notched as W's is... Let's hear it... LUCK.
Now, you can say... "Well, clearly that team is clutch! They just know how to win in the end!"
Well, against UMass, they didn't. Game flow was similar in win probability.

Miami seemed to be in control all game, until a little over 2 minutes remaining. And then they couldn't pull it off.
An emotional narrative would be that they "choked". I don't like emotional narratives. I view these things as a lot more luck/chance than anything. I view winning 9 of 9 that were tight down the stretch as lucky, as the odds given the strength of the team would be closer to 5 or 6 of 9. And then for them to lose 1 of 1 down the stretch as unlucky, given that it's a team they were assigned a 75% win probability over at tipoff, so they should win 3 of 4. Well, this outcome was the other 1 of 4.
Is going "undefeated in the
regular season" a pretty feel good story? Yeah.
Are the odds against other bubble teams going 31 for 31 against that schedule? Yeah, probably. Because to have greater than 50% odds to go 31 for 31 if each individual game was equal probability would require those games to be over 97% win probability, closer to 98%. (.98 ^ 31 = 53.5%)
However, over a lot of seasons there are going to be teams that do it.
Going undefeated against a weak regular season schedule is a statistical anomaly, not an amazing accomplishment. And based on being now 64th in NET after the loss, it also doesn't appear to be a tournament-worthy resume.