Hopefully I can be of help here, it makes sense when you realize Paul is talking about jews and gentiles both being under sin. You can find out quickly by looking up the verses Paul is quoting from the OT that he does not mean to say that everyone is on their way to hell and a hater of God..
When Paul was citing about all are wicked, it was about a time of great apostasy amongst the Jews.
Why?
Gentiles had been seen as inferior by Jews. And, with good reason.
For the Gentiles had been living according to pagan god worship, which led to depravity.
Many gentiles led disgusting lives as a result.
And, when the Jews were walking with God's ways, the nation shined in a world of darkness.
The Jews gained a reputation of superiority as a people.
Jews were not allowed to freely associate with gentiles.
And NOW....
That Gentiles were coming into the fold?
Paul wanted to remove the stigma of their past and to show them that Jews were no better than they were
as long as the Jews did not obey God's laws. Paul wanted the gentiles to shed their inferiority complex before God,
and to see that all when not under God are wicked and depraved.
That is why that passage was written.
As it is written:
“There is no one righteous, not even one;
there is no one who understands;
there is no one who seeks God.
All have turned away,
they have together become worthless;
there is no one who does good,
not even one.”
Romans 3:10-12
What was Paul using to show that Jews without God were no better than how the Gentiles had been living without God?
Paul cited OT Scriptures!
About Jews having gone wrong with God!
Psalms 14:1-3
Psalms 53:1-3
Eccles. 7:20
Grace and peace!