[There’s not a single good person on earth?]
No, not one. Only Jesus Christ alone fulfilled the law and was considered good by God, of whom He Himself said, the good works of mankind may be good but can not save from sin as the Scriptures teach those who read of Jesus Christ, and who believe every Word of God is true and not to be refused.
Matthew 17:5
“While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is my beloved Son, in whom I am well pleased; hear ye him.”
King James Version (KJV)
Does this throw out ‘good’ because it is not perfect?
Since there are no perfect people, it seems excessively Manichean to condemn those who approach but fail perfection as being whatever the opposite of good is. While it may be attractive to those who condemn everything around them, the world is too lovely to traverse it only by holding one’s nose, as if one were above it all.