It seems to me like perhaps Harvin's problem with Ponder is that Ponder didn't have a work ethic close to Harvin's, and since he was a mediocre QB on the field, Harvin probably thought he should have been busting his ass to improve since he had a long ways to go.
If I'm a great talent in the NFL and my QB's not, and not working harder than anyone to correct that; then considering what the QB position is and how it's automatically a leadership position, I'd have contempt for my QB in that scenario, too.
You can't fault a guy who's just not that good if he's working his ASS off to try and get better, and just can't seem to. You can totally fault a guy if he's not that good and doesn't try super-hard to become good, though.
"VICTORYYYYYYY!" -Johnny Drama