Think about Okafor's situation from his perspective for a moment. When he was drafted, he already knew that the team he would be playing for already had two blue-chip centers on its roster, and that the team would purposefully avoid winning for most if not all of the duration of his rookie contract.
Other guys on Philly's roster have had less of a bad attitude, sure. But if he were drafted by pretty much any other team, he'd be exactly what we expected him to be: a dominant post scorer who's a liability on defense.
Team culture matters.