Can anyone summarise why Corbett is so unpopular? All I know is that the Jerry Sandusky case hurt him somehow, but I'm not sure exactly how and why.
1) The Sandusky case: Many people think Corbett slow-walked the investigation so that it didn't interfere with his gubernatorial run in 2010 (he was Attorney General, and actually a fairly popular one, from 2005-2011). Kathleen Kane took advantage of this by pledging to run a full investigation into it, which is part of why she won by such a huge margin. This might not seem like a big deal to out of staters, but it's pretty huge in PA.
I don't get the motives here. Wouldn't it be a big plus for Corbett's gubernatorial campaign to be seen as "cracking down on child molesters"? "Think of the children" is such a successful tactic that I can't imagine anyone intentionally playing against that narrative for electoral reasons.
Some people might not want to be seen as "attacking" Penn State. In Pennsylvania, that's very high risk.