The majority of the “vampyric community” operates under the guidelines of moralistic doctrine referred to as the Black Veil, and are thus hesitant to predate upon a mortal without expressed permission. This leads them to pursue donors—individuals with a basic comprehension of vampyrism who willingly give of themselves unto the vampyre.
In Liber Nosferatu, it is stated that a vampyre who feeds upon strangers is a “parasite,” and the reader is instructed not to feed without consent.
By following such nonsense and seeking out donors, the witch does much more damage than she otherwise would. Most non-moralistic vampyres feed briefly upon various different passers by or deeply on a particularly appetizing one of the same. While a deep feed will result in fatigue and irritability, and can result in fainting, illness, and bruising or irritation of the skin if pursued to the extremes, even deeply feeding on a stranger is preferable to feeding upon a donor.
After all, the kind of person who would volunteer for donation is clearly a kind and caring friend. If the vampyre must select a person to incur detriment, the well-being of a loved one should outvalues the well-being of a stranger. A friend should be afforded a varying degree of loyalty and good wishes and it is errant to treat them like an ash tray.
Moreover, the donor would necessarily be fed upon routinely. Why would the witch want to detriment a loved one regularly instead of causing multiple unimportant people, people to whom she owes no loyalty, enervation once or twice in the course of their lives?
Being regularly penetrated by tendrils weakens the aura of the target and creates permanent weak spots therein. It could even force the donor to take on the vampyric appetite, albeit temporarily.
Psychic vampyres incur certain degrees of stigma amongst certain elements of the Satanist scene, particularly those influenced by LaVeyan or Setian philosophy. It is clear that this stigma rightly belongs to unawakened vampyres, whose Hunger inclines them to histrionic behaviors and the routine enervation of whomever they fraternize with.
Routinely feeding upon the same individuals, whether one is awakened or not, is far more parasitic than what is recommended in these texts.