The hate is there for teams that are really good for a really long time because they have beat so many people's favorite teams. When a team beats your favorite team in a championship or a big semi-final type game, you start hating them. Ask a Duke fan how they feel about UNLV or Arkansas (or Mercer

, I couldn't resist). When your team gets so close and loses it burns that other team into your "hate-memory" forever.
To make it even worse, if the team wins a couple/few championships the band wagon stooges come out of the woodwork. Nothing makes you hate a team more than a group of idiots who really don't care screaming and celebrating your teams loss after you lived and died on every play. The same people who would shrug and say "oh well" and start looking for a new team to root for next year while you know it's going to take all season (if ever) to get over your disappointment. It's infuriating.
There was a TON of this in the Laettner Duke years. People who you never heard talk about college basketball in their lives were walking around with Duke caps on and talking trash like they'd been there all along. Duke is like the Yankees, the Cowboys, the Lakers, etc.. They were really good for a long time and beat a lot of peoples favorite teams and then to add insult to injury you were surround by idiots who never cared before screaming and yelling when they won championships. When you really love a team and suffer through the hard years and then get so close and miss you're gonna really burn against that opponent. Have a few casual band wagon fans mocking you at work on Monday morning and it really sets it in deep.
Laettner was just the face of the franchise at that time. Not only was he all-world (easily the best college player of his generation) but he embodied everything people already disliked about an expensive, privileged private University. He acted just like that rich kid you hated in high school, right down to the superior smirk and attitude on the court. Duke was good, they're beating everyone's favorite teams, idiot wannabe Duke fans (which didn't exist outside of the NC Piedmont a few years earlier) are getting obnoxious. In walks this living and breathing example of what you were already thinking, it was like the perfect storm.
As I get older I find it harder to hate Duke. It's hard not to respect Coach K. He continues to win year after year, there's never been a grade fixing, paid player, sexual assaault, or fake class scandal that I can remember. He preaches defense, team play, foul shots, winning the "right" way, makes kids accountable for their actions (Sulaimon)... all the things us old farts like to complain is missing from the game today. When so many giants fall and legacies are destroyed (RIP Joe Pa) it's hard not to respect a guy that is clean, wins, and does it in a way everyone can respect.
I can't wait to watch the 30 for 30. I've come around on Laettner. It's easy to forget just how great he was in college. All of us Duke haters reveled in his mediocre (at best) NBA career but his overall dominance in the college game was an amazing thing to watch, I'm glad I got to not only see it but see probably it's most famous moment in person. When I hear him interviewed now I have a lot of respect for him. He's honest, still has a little swagger, but seems to have some real perspective and owns everything he did, good and bad. I'm not going out to buy a throwback #32 jersey for this weekends games but years later I have a grudging respect for Laettner and I almost like Coach K (although i'll never admit it out loud, in public).
Saying that....
Go Robert Morris/North Florida!!! I can't say I wouldn't be giddy if Duke was the first 1 seed in history to go down, and I have knack for being at history making games