Why will God's coming wrath be absolutely fair and just?

Les explains that in the near term, we do not know how soon, but it feels close when God will pour out His wrath. He says it will not be an instantaneous destruction like the flood; instead, it will be His wrath, causing mankind such suffering and mental anguish that Revelation says they will cry for the rocks and mountains to fall on them, and cry for death but it will not come, because God is bringing down His wrath on Christ-rejecting mankind. Les emphasizes God will do it in absolute fairness, in justness, because there are more people living on the planet right now than probably lived all the way back to the time of Noah. He notes the population is over 5 billion and rushing toward 5.5 and 6, whereas at Christ's first advent there were probably less than 500 million in the then-known world—only half a billion after 4,000 years of human history and 24-2600 years after the Flood. That 500 million did not double to a billion until about 1860.