Just so you know, psychopath and sociopath means the same thing – sociopath is the outdated term. These people do not experience emotions like other people. They don’t feel love, remorse, or regret. It’s easy to kill if you truly don’t give a shit. What makes a psychopath a psychopath? No one knows. Nature vs. nurture as usual.
Not only psychopaths kill. Only 1–2% of prisoners are psychopaths. Over half have antisocial personality disorder, but these are two separate disorders.
So, why do other people kill? Money (life insurance, for example), love/jealousy, power/control, mental illness, heat of passion, hatred, self-defense, neglect…
There are so many reasons and there’s no one right answer. I’m currently taking a criminal justice course called Analyzing Homicide. People who kill their intimate partners, parents that kill their kids, kids that kill their parents, confrontational homicide, serial killers, etc. There isn’t always a motive but, when there is one, it varies from perpetrator to perpetrator.