We already know that a vampiric strain has mental effects- blood dragons are seemingly all obsessed with combat, strigoi are all animalistic, necrarchs seem to be obsessed with research, ect. Notably they all seem to have character traits that echo the founder of the bloodline, which makes me think that the process of embracing makes someone mentally more like the founder of the bloodline embracing them. It seems not a great leap that that process would also include the particular morals, or lack thereof, that the progenitors possess.