By contrasting those two attitudes, we see the typical altruism vs egoism paradigm of morality due to vampirism being a self-centered gratification at the expense of others. Therefore, we can safely deduct that being in good terms with the concept of the Void, one favors individuality, self-empowerment and generally a stand-alone perspective, as opposed to the Light's mentality.
My sources for this is general lore/philosophy of the Light/Shadow duality in the Warcraft universe in addition to some wonderful clarifications made by the Chronicle Vol.1 which was released last month.