Why does God have every right to pour out His wrath on humanity?
God has every right to pour out His wrath because He has already accomplished reconciliation for every person and done everything possible to make salvation as simple as possible. Lost humanity only has to believe and appropriate that reconciliation, yet when people reject it, God's judgment is fully justified.
Les explains that, as God is concerned, every person who has ever lived so far has had reconciliation accomplished. All they have to do is believe it, to appropriate it. Because God has done everything possible to make it as simple as possible so that lost humanity can come back to Himself, He will have every right in the world to pour out His wrath. He also points to verse 6, asking how God shall judge the world, and affirms that God is going to have every right to. The context further notes that even a religious zealot like Saul of Tarsus had to be told he was a sinner and undone, and that the Gospel of Grace does not mean people may live as ungodly as they want.