>>84164312Because they want nice blood not nasty shit.
They want a lovely fresh claret from a young fresh beautiful woman.
You never see a vampire break into a fat neckbeards room to drink some mountain dew poinsoned diabetus juice.
I'm sure they CAN sustain themselves from period blood but probably as a last resort.
Same as how me and you wouldn't forage for food in trash cans unless we absolutely HAD to.
