It is not entirely clear how it is that positing unseen and undefined entities that infect human minds by unassessed processes involving the entities’ own quest for transmission and that cause people to do things that transcend their genetic imperatives is fundamentally different from medieval demonologySo: memetics shares a considerable amount with the ideas of demonology and possession.
Memetics posits that people can become infected with foreign entities that are bad for them - and can manipulate their behaviour and personality. Sometimes deprogramming them requires interventions by friends and family which superficially resemble exorcisms.
Indeed, in addition to resembling these old ideas, memetics helps to provide a scientific explanation for the psychological phenomena that caused the reported cases of supposed demonic possession - helping to explain the association of reports of these phenomena with witchcraft and satanic cults, for example.
Of course not all such cases would necessarily have been socially-transmitted - but in many cases they would have been.
So: the resemblance is no accident - many cases of supposed demonic posession would have been associated with infections of deleterious memes - and the exorcisms used to eliminate them were a primitive form of what we would now call deprogramming. This is an example of a case where folk-medicine contains some useful information.
Of course a significant difference is that those involved with exorcisms tended to buy into a supernatural mythology - whereas those who do deprogramming ususally recognise that they are dealing with disorders associated with harmful belief systems which have a naturalistic origin.