They have more losses, but they've also played a tougher schedule. You know how in football SEC fans will trot out "ain't played nobody"? The ACC does that in basketball. Their tougher schedule is also why they have more quality wins, but then again, they've won those games.
Tennessee only has what I'd call 2 really good wins - Gonzaga and Kentucky. Rightly or wrongly, the Gonzaga win can lose value over time because of recency bias. Duke has beaten Kentucky (season opener), Texas Tech (late December), FSU, and Virginia twice. They do have more losses than Tennessee, but I'd only say one of those wasn't a good loss (Syracuse).