The vast majority of psychopaths are not criminals. A total disregard for the thoughts of others, a lack of empathy, can be an advantage. Bankers, lawyers, politicians, even some doctors display aspects of psychopathy.

When you are in hospital after a bad car crash you don't want to be treated by a Doctor who 'feels your pain'. You want that cold and calculating mind to take decisions based on facts rather than emotion. Most psychopaths find their niches.