“By no means! For then how could God judge the world?”
Paul answers the objection to judgment upon the Jews. Quite simply, he answers that if God doesn’t judge the Jews, he can’t judge the Gentiles. That means everyone gets off free from punishment for their sins.
If God allows that to happen, he is not just. If he’s not just, he can’t be love. For love demands justice occur. If everyone gets away with their ins unpunished, God is not God.
The world is then in chaos. Everyone lives as they wish. Evil prospers.
This thought can’t even be entertained by Paul. It shouldn’t be tenable for any thoughtful person.
We all have sinned and will one day face God’s judgment. That can be life’s only fair position.