This is the best argument I've seen yet. The argument that Paul is using hyperbole. I struggle with this line of thinking and here is why.
Paul fully believed and taught that righteousness was a free gift that had nothing to do with our actions. Unmerited favor where we have nothing to do with it.
Now, after deceptively quoting Scripture to try and convince us that no one can become righteous under the Law, Paul is left to find for us a good working reason why God gave man the Law in the first place! Here is his logic.
"Now we know that whatever the Law says, it says to those who are under the Law, that (for this purpose) every mouth may be stopped, and all the world may become guilty before God. Therefore by the deeds of the Law no flesh will be justified in His sight, for by the Law is the knowledge of sin." Romans 3:19,20
This begins to defy words to describe the blasphemous lie that it is. But hey! Paul has to come up with some reason for the Law's existence after demolishing the truth! Are we really to believe now that it is God's purpose to make man guilty before Him? If God intentionally made His Law impossible for man to keep, that would make God the author of unrighteousness and guilt!
So the idea that hyperbole was being used here doesn't fit for me in the end.
Well, one thing I think of Paul trying to do here in this epistle -- he's writing to the Christians in Rome, and it's to both gentile and Jew,
but especially to Jewish converts, because Paul knows from first hand experience that many Jews that have converted are still quite naturally tending to want to reestablish or continue their old habits of being good by willpower following the Law -- a self created righteousness. Soon, they may insist on circumcision for instance (just 1 example).
Contrast to Christ speaking of how we are able to bear good fruit, or true fruit -- the
only fruit of any value -- in the key John chapter 15, verses 1-17 (reread if you haven't in a year or more): we are able to bear real fruit only if we are...remaining in Him, in faith, by virtue of His being in us, His word remaining in us, we remaining on the Vine, abiding
in Him.
That's not a self-accomplishment on our own without Him, but a new kind of thing, fruit, that we have because and from and through Him -- very much like branches receiving nourishment through the main stem, the vine. The branches produce fruit because the Vine feeds them. The fruit is the outcome of the branches from the Vine, since they remained on the Vine. In Him.
This is very radically unlike the old Jewish covenant way, from which the converts Paul is really writing to are from. They need a total reset of their feeling/mind relationship to the Law.
Now, today in 2019, we see too much of a kind of opposite problem actually, doctrines based on bits of what Paul wrote, ignoring what Christ, James, John, Peter and Jude wrote (and...things Paul wrote even!). One way to aid them is to quote what Christ said -- for instance Matthew 7:24-27. Another is to get more interested in the powerful and valuable epistle 1rst John. James is so blunt, I don't alway think of it first, as the message they need, but it can help at times.