It does something - other movies won't. It is harsh comedy - most of it most certainly disgust the very mainstream moviegoers.
Justice - it is like somehow a dream comes true.
A decent man gets pushed over the edge.
His neighbors are the worst people on earth - their baby is an evil abomination.
He gets fired for absolutely no reason and finally is diagnosed with terminal cancer.
But instead of ending his life - he decides to end the lifes of the ones not worthy of living.
Just watch the trailer - and the movie!