Many (though not all) of the people insisting that Sears should have handled his departure with more class handled Sears' departure with very little class themselves.
People here criticized his Mom publicly. They said he didn't care about education or family. They said he only cared about money. Called him Jaaron Simmons 2.0.
Out of one side of their mouths, they insisted that Sears show OU loyalty, and then out of the other, criticized his game and started actively rooting against his success wherever he ended up.
Notably, most of those criticisms began before Sears made his choice or announcement, so the "he didn't handle his decision with class" is a retroactive justification.
BINGO
The criticism of his departure is fair. Fans have a right to express opinions.
Last I checked, there was no formal announcement. He took the approach that he didn't owe OU anything, which I believe is why his decision was met with harshness. He could've saved some face by issuing a statement and owning his decision to leave (instead of having others do it for him). There was no closure at all.
Rooting for him to fail is a moral issue that only those who share this sentiment need to cope with.
That being said, not sure I remember seeing anybody actively root for him to fail? I've seen some comments stating he was a non-factor in big games for us (me included) but not sure I can point to any specific post celebrating his failures.