Now see I got the complete opposite impression. Joker's saying "I'm not responsible for what I am, I had a really bad day once and it made me this, Batman had a really bad day once and it drove him insane too, I'll prove it by giving Commissioner Gordon a bad day driving him insane."No it's a terrible Batman story all about how Joker is right, and Batman's just as insane and wrong as he is.
Except he's wrong - yes Batman was traumatized by his bad day but he found a way to cope (admittedly dressing up as a giant bat and punching criminals in the face isn't a coping mechanism that would work for most orphans), and Gordon wasn't broken by everything Joker did. The whole point of the story is to show that Joker is wrong.