then why make sociopaths a subset of narcissists? it adds absolutely nothing to what he was saying. they could be completely separate sets and it wouldn't change the argument.

the wikipedia page on narcissists has no mention of sociopaths - http://en.wikipedia.org/wiki/Narcissistic_personality_disord... - while the page on sociopaths only mentions narcissists as a possible subtype or coexistence - http://en.wikipedia.org/wiki/Antisocial_personality_disorder

in short, when someone on the internet says contradictory things it's much more likely they are half-remembering something they read in a magazine five years ago than that they are a subject expert.

I was only objecting to the way you presented your criticism: that one category couldn't be a subset of another because the subset seems to lack a feature that the superset has. Criticize for the right reasons, etc.