Grant Morrison is a respectable writer, but I do not always agree with how he interprets certain characters or books (leather clad non-super hero X-Men come to mind). I can't say that his perspective is invalid...but it is not congruous with other interpretations, including his original take back when Bill Finger and Bob Kane handled it.
"The Joker is a master
criminal, initially portrayed as a violent
sociopath who
murders people and commits crimes for his own amusement."
That was his original take. Here is a more contemporary take from Paul Dini and Alex Ross.
"The
Paul Dini-
Alex Ross story "Case Study" proposes a far different theory. This story suggests that the Joker was a
sadistic gangster who worked his way up Gotham's criminal food chain until he was the leader of a powerful
mob. Still seeking the thrills that dirty work allowed, he created the Red Hood identity for himself so that he could commit small-time crimes. Eventually, he had his fateful first meeting with Batman, resulting in his disfigurement. However, the story suggests that the Joker retained his sanity, and researched his crimes to
look like the work of a sick mind in order to pursue his vendetta against Batman."
I also don't support the idea of Joker as being a sympathetic villain, due to the circumstances of "A Death in the Family." He beats Jason Todd nearly to death. Blackmails Jason's mother into helping him extort medical supplies from a desperate population. Sells said supplies on the black market and replaces the ones given to the needy, with Joker gas. He then accepts a position as Iranian Ambassador, thus giving him political immunity. That is a little too well thought out for a man who supposedly creates his own reality on a day to day basis. Grant Morrison is a wonderful writer, but this time, i'll have to say that even his writing is wrong, in the face of established legacy and continued legacy from that point foward.