I think Yung fairly completed the job. This true case might be occasional, but there were groups of marginalized classes of people behind the story. They are poor, poorly educated, struggling to make a living, with little hope about their future. The class of people are the lowest in the society, and what would they do if they always feel themselves hopeless? Sometimes, to kill or be killed might be a better choice for them.
This is a desperate movie, and it is worse that the similar tragedies might take place around us if no one tries to learn something from it.