A fear pointed at a category rather than at a person is the dangerous kind, because it never has to check who is actually standing in front of it.

What the research says

A meta-analysis of youth aggression found that empathy had only a small inverse relationship with aggressive behaviour, while callous and unemotional traits predicted it more strongly. So the comfortable explanation, that people who harm others simply feel nothing, is too simple. The review covered young people, and it maps what predicts aggression rather than what stops it.

Strength of evidence: one line of research. A single study, or a theoretical account.