It actually takes real talent, to not go around saying destructive things. JWs go from door to door, telling people that the world is about to end. This is not productive, even if they are well intentioned. Since 1870, they have been going around depressing people, and telling them that science is wrong. Typically, people who believe that the world is about to end, don't get on with a real life.
Most people exude non-self-aware bitterness and insecurity, rather than 'evil'. To be 'evil' you have to deliberately manipulate people to destruction. Even if more self aware people attempt to pretend to be objective, the advice they give others is bent by their initial assumptions, which will not change, and their perspective, which is likely always be badly calibrated. There are some people who have a knack of saying the right supportive things, and these people likely score highly in emotional IQ tests. Given the prevalence of Aspergers, and the tendency of females to be more empathetic, this is genetic, not something that a person has any real control over.