Jokers impact on people is underlooked and he is a good person at heart due to the fact of narrators intention and purpose of the character being objective to the narrators. When the narrator or author makes a character for a purpose than that's their purpose and thats undebatable. The author of DC created Joker to be the antagonist of Batman in which even batman stated, "without joker there is no batman" so all impact created by batman roots back to Joker and batman objectively changed lives. Jokers purpose of being an antagonist for someone good from the author makes him a good person due to its correlation back to Batmans greatness. Actions dont define a person as shown with their true intnentions eventually getting bended by society like Obito from Naruto.