This is THE entire problem. Too many people in this nation do not know what sin is. The liberal left only believes evil (sin) is what they say it is at the moment to suit their purposes.
God, through Isaiah, had a warning:
Isaiah 5:20 Woe to those who call evil good, and good evil; Who substitute darkness for light and light for darkness; Who substitute bitter for sweet, and sweet for bitter!
Proverbs14:16 A wise man fears the Lord and shuns evil, but a fool is hot headed and recless.