That doesn't mean its not inspired or unreliable. If one account is unreliable, then so are all other accounts, a little leaven, leaveneth the whole lump. It just means that our assumptions about who said what are wrong within the narrative.
Yet we have such as:
2Ti 3:16 Every Scripture is God-breathed, and is profitable for teaching, for reproof, for correction, for instruction which is in righteousness.
Do we include the NT in this, or only apply it to the OT.
I have an understanding that the Bible is a collection of words formatted as stories similar to any other book. They are true stories for sure, but stories nonetheless. If we treat the Bible in similar fashion, then understanding it become easier. You can't have it both ways, there are either some righteous or none at all. Scripture doesn't contradict itself, and God is not the author of confusion, so there certainly must be an explanation for such verses.
Indeed, there must be an explanation. However if we relegate them to "stories" and allow ourselves to pick and choose that which we accept and that which we wish to attempt to explain away, the "stories" cease to carry any authority.
Since we can't have it both ways, and "none are righteous", thus also it is true that "none seeketh", which if we are to apply that according to the measured used with regard to "none righteous", we are left that not even one of us seeketh. If we wish to exclude or attempt to explain away one part of Luke, can we not also then attempt to explain away some of Paul. That his writings are "stories".
@Stranger has already provided "reasonable" explanation. Did I really just say that? <chuckle>
Also consider as a difference: "who trusted in themselves that they were righteous" [ cf Luke 18:9]
Further, Jesus himself said he did not come to call the righteous, but sinners. thus who are whole have no need of a physician, but those who are sick. That does leave open the possibility of some being "righteous" / whole. Those who didn't trust in themselves that they were righteous. Consider Simeon, Joseph of Arimathaea.
However, we could also examine Psalm 14, to see if we can understand / discern what / who David was speaking of / referring.
We assume that this is God saying they were righteous, but we don't see God being referred to as the one saying it. We don't see terms such as "and God said" or "the Lord said" for instance at all which is what is always seen when it is actually God speaking. Therefore, it is safe to conclude that God wasn't the one that claimed them to be righteous, but is coming entirely from the narrative or perspective of Luke.
And thus, each of us would be allowed to attempt to use such to exclude / explain away anything that we don't care for, or that we don't want to accept.
Once we begin to undermine ...
I have witnessed people attempt to claim that the words of Moses were just that, only the words of Moses when the text clearly said of the place in question: "And God said ..."
