What is the point of this movie?

Rating: 4/10 (14 October 2019)

Is it that the Joker is justified in becoming a serial killer because he was abused as a child and was attacked on the street and on the subway?
Or is he justified in becoming a mass murderer because people didn't laugh at his jokes, and a famous person made fun of him on TV about not being funny?
Or is it that we should be more careful about letting a mentally disturbed person get a gun?
Or is it that we should prevent a private person from giving a gun to someone else without official background checks?
Or is it that our society is so messed up that one logical response is to become a wacked-out maniac who goes around murdering people who have done him wrong?
Or is it something else?
One thing it is NOT, is entertainment. This movie is about as enjoyable as swimming in sewage.
The 4 stars is because it was well-written, the plot was logical, and it succeeded in making you feel bad for the Joker. And because Joaquin Phoenix did a great acting job.
But what is the point of this movie? Is it to say that we must stand by as society collapses into a putrid mess? That the bad guy will ultimately win? No thanks.