Beware of logic leaps.

Psychopaths are able to identify victims does *not* logically imply

All who can identify victims are psychopaths.

It would be easier with venn diagrams to illustrate this but not going to create one just for LJ.

The ability to notice and interpret body language is just that. Some people may be good at it naturally. Others may be able to learn, if only to learn to pay attention.