I'm actually not familiar with this ENTP stereotype. I don't think it comes from socionics.

Psychopathy and other "sicknesses" follow patterns based on type. In psychopaths the leading function seems to be totally blown out of proportion to the point where it knows no restraints and is seen as being such an important end that it justifies any means. Also, in many cases there seems to be a traumatized weak function that the entire world must pay for.

Also, type influences, for example, whether the psychopath performs carnage with a symbolic bent or for a concrete purpose (or out of rage). This article shows that the boys (actually, Harris) saw their mission as being symbolic -- striking fear into the nation and attacking a symbol. It seems likely that his partner was more concerned with the actual physical execution and venting his rage. [/code]