It's simple really:
He is Notre Dame's highest profile player in years.
He had received a ton of press for showing outstanding character.
Notre Dame is the most polarizing force in college sports.
The millions of people who don't cheer, cheer for old Notre Dame bring more than just their opposing athletic fandom to our grinding wheel. They bring all their political, philosophical religious and moral axes with them.
It was almost inevitable that at the peak of Manti's (Notre Dame's) positive coverage, that if someone didn't find a chink in Te'o (Notre Dame's) armor, they'd create one and get at us by knocking him down in the public eye. They have a position on Notre Dame and the only thing they'd hate more than being proven wrong is to see Notre Dame proven right in the public consciousness.
When we communicate to the world through words or actions that we intend to do better than the crowd, the crowd will accuse us of arrogance and hypocrisy. Then they will do whatever it takes to drag us down so they never have to ask themselves or explain why they don't try to do better themselves. This whole circus has very little to do with Te'o. He's the straw man. Notre Dame, what it stands for and the positive coverage it receives for attempting to do better is what they're after.