Because thought provoking themes are given in a gripping narrative:
Where should the line be drawn between seeking justice and pursuing revenge?
How grief can lead to desperate, sometimes destructive actions? How differently people can deal with the lost of a loved one?
How conflict can cause the same people to be good/kind and flawed/immoral simultaneously?
Are people, who are supposed to lead/protect us, accountable when they are incompetent for their jobs/roles?
Whether individuals who have done wrong once can redeem themselves and what true redemption requires?
How racism and social bias intersect with and influence other societal problems?
On top, individual performances are great complementary joy to its philosophical screenplay.