First off, Penn State has nothing to do with this shirt. It's being sold at off-campus stores that aren't sanctioned by the university.
And yes, the NCAA may have stepped a bit outside its boundaries with the penalties it levied against Penn State. But anyone that buys/wears this shirt realizes they're opening themselves up to ridicule regardless.
On top of all that, it's grammatically incorrect. The NCAA would be overstepping its bounds, not their. Lame, guys.