And why would it be better to contradict the truth revealed by God in the scriptures, which plainly states that all have sinned?
Yes, it clearly says that all have sinned, as you point out. But I think you would agree that Paul is speaking about adults here. I cannot imagine in his mind, or any reasonable mind, that he would imagine that an infant being held by his mother has "sinned and fallen short of the glory of God." Can you?
Children are not sinners. Jesus himself declares that unless we become as children we shall not enter the kingdom of God. "Go and sin no more," is an invitation to become as a child. Why, if human beings are inherently evil, or "sinners" by nature, would he say that? If we are sinners by nature, that means children are too. I do not believe they are, nor do I belive adults are either. We are after all, made in the image of God, and God is good by nature, not sinful.
It doesn’t say people are “inherently evil”. It says that everyone falls short and sins and is in need of a Savior and Jesus Christ came to save sinners.
But the doctrine of "original sin", which the vast majority of Christian theology adopted from Augustine in the 4th century A.D., views humans as "sinners" by virtue of inheriting the sin state from the Fall of Adam and Eve. That view, that doctrine, that teaching, tells us that humans are sinful by nature. And when we say that humans are "sinners", that is branding us as inherently bad, not inherent good, nor even just neutral. "Sinner", says this is what you are by nature. You are a bad person. Not a good person, who did bad, but a bad person inherently.
That is what the doctrine of original sin tells us that human beings are. And the language of calling people "sinners" reinforces that image, just as saying to a child, "You're a loser", will head that child right down that path of living up to that label. It says to people, you are by nature a failure.
When we brand humans as sinners, we are saying, sin is not something you've done, but something you
are. It brands humans as a negative creature, bad by nature. It tells us that is who and what we are. Do you see the difference?