When people become more depraved and cruel, they also invite more calamity upon themselves.
The delay of calamity allows for the further increase of depravity and cruelty.
While the victims endure these hardships, they gain rewards they cannot earn through worship and other deeds in this world, and this is a Mercy for them;
The same event is for the oppressors to bear the consequences of their injustices for eternity.
The judgment is passed!
The oppressors will face eternal torment, while the oppressed will attain eternal blessings.