All men know this. When they are injured by an enemy, they are angry. When they are well-fed, they are happy. When they steal from their neighbor, they know they are crossing a line. I agree with you. A true sociopath is rare and is a thoroughly aberrant mental state.
But we're talking about mankind here. And since the fall, every man's conscience is impaired and self-serving, and no man's conscience will step outside its own egocentric orbit to love God unless and until God radically changes that conscience from self-worship to God-worship.
Why did Paul spend so much time explaining the differences between the natural man and the spiritual man if those differences are not real and founded within God's own purpose?
Let men claim they have the ability to do good. I'll continue to believe it is "God which worketh in (me) both to will and to do of his good pleasure." (Phil. 2:13)
And the difference between the two, rather what is good and bad. X is bad; Y is good. X is wrong; Y is right.
Unless we're speaking Eubonics, a conscience means bad hurts your conscience - else you have no conscience.