I think it's because you lost the ACC regular season by 3 games to UNC. Even with an unbalanced schedule, a bit much. Loss at home to last year's NC State team almost counts as 2 (kiding, no offense Packfan, but you weren't too good last year as you'd acknowledge; Keatts will get'em right). And somewhat moots the unbalanced schedule argument. OK, 2-1 head to head. And 15-7 against ACC teams versus 15-5 for UNC if you count the ACC tournament. So quite close with the unbalanced schedule, but again the NC State loss hurts. Georgia Tech wasn't a great loss for UNC but they played a bit better than thought in the league (blow-out loss to you guys excepted), and that was a road loss. Anyway, the 2-1 head to head, so against everyone else in the ACC Duke went 13-6, UNC 14-3. Close. I can see the argument. But it wasn't a "no way no how" thing I think.
As for South Carolina, very tough to play them in SC as 7 seed, no doubt. Although Arkansas, 8th seed in UNC's bracket, was 12-6 SEC, 25-9 pre-tournament. South Carolina was 12-6, 22-10. And had gone 2-5 its last 7 pre-NCAA's. Arkansas had gone 8-3 its last 11 pre-tournament. Including a win at South Carolina, true road game. And almost beat UNC.
Given how it played out hard to say the choice was all that wrong. Even if it may have had some bearing on how things played out. I get your blood boiling. And that you think there's no way UNC should have had the number 1 seed over Duke. It's hard for me to be objective but to me it's a very close call and not necessarily the wrong one.