One of the truths that JudeoChristians believe about God, is that He is Holy, perfect. He knows no sin.
Given that God is Holy, it is reasonable that He judges man, not by some bell curve, or by the balance of good and evil in a persons life, but rather by His only standard, perfection.
Given that the standard is God’s Holy perfection, it is reasonable that He finds all of us guilty. It is also reasonble that once having sinned, there is nothing we can do to make up for it. As anything that we know to do that is good, is only what we should have done in the first place.
Finding ourselves condemned with no hope of saving ourselves, our only hope is that God saves us. And fortunately He did, when He came to earth as Jesus to pay the price for our sins.
Lovely presentation of the Gospel. :)