There's a lot written about this in other places, but the gist of it: many ancient "rituals" are based around pre-medicine hygiene practices. In this specific c

There's a lot written about this in other places, but the gist of it: many ancient "rituals" are based around pre-medicine hygiene practices. In this specific case, live slaughter was the norm because of the health risks of eating carrion: if you haven't seen the animal alive, you don't know how long the meat has been dead before consumption.