I too initially thought along the lines of hasnamuss individuals representing psychopaths, but over time I came to feel the term as encompassing or subsuming psychopaths - at least in terms of their functioning and their effects.
In fact, IMO, a deep understanding of the true nature of envy (in my mind, a term which is not functionally related to 'jealousy' in any way and can be described in BT's pp. 405-406) will reveal a 'set' of individuals most destructive to life in general and to man in specific, whether psychopaths, certain individuals otherwise labeled as sociopaths or whatever. To my understanding, this 'envy' is a poison core of desire to destroy 'the good' just because it is good; because the existence of any 'good' threatens to expose all distortions of 'truth' which have so many people spell-bound.
Also, I sense that, to Gurdjieff, it's not a name that's important (remember his comment about 'orange wranglers' aka 'grammarians') so much as the ability to cognitively arrive at the 'source' from which these various names or labels arise. By 'source' I refer to an implicit cognizance of an individual's relational intelligence and activity which we often refer to as "by their fruits...".
With respect to G's language of form with which he presents BT, it seems clear to me that his story is an example of how one's representational (symbolic) consciousness and one's own relational (contextual) intelligence can work together in unity towards the accomplishment of aim. And I feel like at least one of G's aims is to awaken or deepen the relational intelligence of his readers by providing this form of metaphor-izing and analogizing experience. A discovery of psychopaths by whatever name a reader's contemporary scholars may identify such a person, could only naturally follow from that awakening, OSIT.
So, in summary, I learned about psychopaths before reading Gurdjieff, so my view is retrospective, but even so, I don't sense anything really missing in his teachings.
My 2 cents, FWIW.