Numerous reasons and they snowballed. UT's over-cooperation in the Pruitt investigation took LOIC off the table and UT did not expect a Failure to Monitor. Tacking that on and raising the fine at the end was a blindside-- and it was unappreciated. UT agreed to the penalties to end it, but instead of ending it, the NCAA ramped up the NIL investigation they had been backstaging for months. They kept digging and digging, bringing other marquee programs and other coaches' recruiting violations into the investigation. They tied it all together to make a case for LOIC and threatened UT with that, claiming multiple L1 and L2 violations in multiple programs. They were coming after UT, they were coming after the revenue sports and they were coming after Nico.
Not only do these alleged L1 and L2 violations reflect negatively on coaches that UT thinks very highly of, LOIC reflects directly on Chancellor Plowman and AD Danny White. The Pruitt violations were not on them nor on coaches that run clean programs, but these newer allegations put the blame squarely on the current leadership, alleging that they do not have institutional control.
UT has made a huge investment in running everything "the right way," and the chancellor has investigated internally and believes UT has self-reported all violations. The NCAA's claims and the way they have gone about everything makes it personally and highly offensive. They're calling people's character and integrity into question, and the chancellor, AD and president have made it clear how they feel about that. UT will fight and it will fight hard.