I don't use it as a pejorative, but it is a subset of "true believers". I don't think that is hyperbolic at all.
And, as much as I like Sanders and his message, he's not a true "leader." He wants to be, and he now has "followers" who believe in the same things he does. What he needs, though, is to give them direction. That is what a leader does. I subscribe to the principle of leadership as "a process of social influence in which a person can enlist the aid and support of others in the accomplishment of a common task".
Right now he is just a spokesman for a nascent movement. He's identified goals, but has not developed a plan to get there. That is what he has often been criticized for. Leadership is what gets things done.
Pray tell, dear fellow, how does one become a leader?
