"In Greek mythology and religion, the term daemon was ubiquitous, referring to supernatural agents or intelligences, lower in rank than a god and holding a middle place between gods and humans, such as the Corybantes, Curetes, Dactyls, Satyrs and Sileni. Spirits of forests, rivers, glades and mountains, as well as cities presided over public and family life and were also referred to as daemons. Daemons could be either good or evil, but even good ones were believed to be capable of evil acts if angered by humans."
"Daemons could also be ministering spirits, god like beings, souls of dead persons, or familiars (companion or helping spirits that take on animal forms). Gernerally they were considered by the Greeks to be protective and attending spirits much like guardian angels or Plotinus's notion of tutelary spirits. In addition, gods themselves are invoked as daemons in certain texts."
So, in short, when a daemonologist such as speaks of a daemon, they are not speaking from a Christian Doctrine position, that is, they are not referring to the non-corporeal entities that are spawned in the bowels of hell that are pure evil in nature.
Instead of accepting the norm , Daemonologists in practice attempt to sever the ties that Christian ideologies have placed upon the understanding of the universe. They have sought an older, more encompassing definition for non-corporeal entities of all shapes and forms. They do not see pure good and evil, only varying shades of gray. Therefore defining all non-corporeal entities as either purely good (Angels) or purely evil (Demons) is ridiculous. Daemons, like humans are every shade of everything in between. Black and white universes do not exist to the daemonologist.