That's a good question. I would say that 'Romans' is a metaphor for 'Barbarians'. Except that to be truly perverse often needs more 'culture' than simple barbarians can muster. Tiberius, Nero, Caligula, and Elagabalus were quite debauched. Then there is the son of Marcus Aurelius, Commodus, as dissolute as any.
Here we have also to consider the Greek schools and their attempts to educate the Jews of Jerusalem, The Maccabean revolt commemorated by Hannukah is a story of rejecting the wrong schooling.
At that time, Israel was God's chosen people and under covenant with God, and all the other nations and peoples were under the sway of the devil.
Now today, all nations and its peoples, including Israel and its jews are under the sway of the devil, (like intoxicated and mentally blinded and stunned by the devil to do his will and are restrained by God) and only the born again, born of God people are of God. To be of God, means your born of God and have been chosen to be His, you have been given an understanding to know God and Christ, and so then are part of His family and He is saving you from the wicked and perverse generation around you. Of course some Christians partially join themselves to the world and might suffer like Lot did living in Sodom, note v21.
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18 We know that whoever is born of God does not sin; but he who has been born of God keeps himself, and the wicked one does not touch him.
19 We know that
we are of God, and the whole world lies under the sway of the wicked one.
20 And
we know that the Son of God has come and has given us an understanding, that we may know Him who is true; and we are in Him who is true, in His Son Jesus Christ. This is the true God and eternal life.
21 Little children, keep yourselves from idols. Amen.
New American Standard Bible
We know that
we are of God, and that the whole world lies in the power of the evil one.
King James Bible
And we know that we are of God, and the whole world lieth in wickedness.