Deformation of character maybe?? Some of the allegations where terrible .. I actually felt sorry for Peter when some things where posted ..
I think Krusty has a terribly deformed character (I'd go so far as to say 'twisted', along with her deformed body and face from far too much plastic surgery), but where these allegations against Pa were concerned, if they really were so terrible and clearly slanderous or libellous, I'm sure he could and would have sued for defamation of character. Maybe he is? Who knows?