Why are people counted as sinners even if they have not committed a sinful act?
People are counted as sinners not because they have actively performed a sinful act, but because they are children of Adam. Inheriting Adam's fallen nature, they are born with an old sin nature that opposes God, doing the opposite of what God commands and doing what God forbids.
Les teaches that a person is not a sinner because of anything they have done so far as actively performing a sinful act. Instead, they are a sinner because they are a child of Adam. Being a child of Adam means having the old sin nature, which always opposes God: everything God says to do, old Adam says to do the opposite; everything God says not to do, old Adam says to do it. Les notes that millions of people are good people outwardly—beautiful homes, beautiful families, well-behaved kids, never cheating anyone, never being unfaithful—and from all outward appearances they are good people. Yet that outward goodness does not change the fact that they are still sinners by nature. Les then attempts an illustration of a well-trained, well-groomed horse and its proud owner at a show, but the context ends before he completes the point.