I thought they extract it directly from the brain, not drink the blood. Maybe both though. In any case, the drive behind this is vampirism, plain and simple. What has been written in Dracula and similar 'fiction' especially of that period between the Victorian Era and the Industrial Revolution, on the tail winds of a revitalized Theosophic movement, soon followed by spiritiualism, electric lights, and relativity.
Authors of these 'fiction' (see also 'The Beetle' by Marsh and 'Dope' by Sax Rohmer, both initiates writing in code), there are truths hidden in the fictional account. So consider this substance that gives them a high, energy, youth, and whatever else they claim. They become addicted and need more - what do vampires do? There are many parallels if you look beneath the fiction. So yes this is ancient, evil beyond evil, and religion has often been used to cover the INNER churches, where these infernal things are done.
Sadly I believe the trafficking is not only related, but that these dark networks and practices are as ancient as the cults which practice these acts. They only adapt over time to changing conditions and make use of opportunistic improvements in technology just like any other enterprise.
These people live in the nightside world. Their ego absorbed by the subconscious which has become dominant, no longer subconscious. This is where the primitive drives, reptilian, bird, animal powers are activated with all the primal instincts of survival fully active in jungle law mode. They generally descend from the Qayin bloodline, but not all of them, some can be initiated or incarnate into different families along spiritual lines. This is but a small glimpse of what we are up against and what this world is really about.