If your society rewards sociopathy (or psychopathy), it is reasonable to become antisocial, nonempathetic, and egotistical.
Then why are we not all psychopaths? Social or familial values counter the destructive values of mercenary conquest.
We divide our life, pushing for both worldly success and relational solidarity. If not assimilated (synthesized) the dueling pressure can produce a schizophrenic split, allowing you to be alternately psycho and nurturing.