That’s probably most;y me. I have explained this is detail from an energy working perspective here - it’s te first post in my journal though not the only one: Maulbeere's Ramblings and Shiny Things
The TL;DR version:
- “Vampirism” is merely a subset of energy working, taking energy from other beings
- Other beings, especially humans, are imbalanced
- So you are taking imbalanced energy
- No, you can’t “filter” that - you can filter the unwanted, you can’t add what is missing or fix poor quality
- You become imbalanced
- The pity is, the cosmos is the best, most abundant source, it’s right there, and the above is unnecessary harm to you an others
No not usually. If they are an enemy, why would you want thier fucked up energy inside you? How is that not revolting? Dump it into the Earth. I find “eating” parasites vile as well. Maybe that’s just me.
I think people have taken the primal allure from the symbology in fictional vampires, and made an occult philosophy around them that’s not real and isn’t healthy. I love fictional vampires, I’m goth I’m all over that, but it’s not sane or sensible to try to shoehorn a romantic aesthetic into real energy working.
“Protect your energy” is a thing, and this is not how you do that.
There’s a caveat: what if your human source was actually clean and balanced? This is why monks can be targets, and concubines were cultivated by the Yellow Emperor - he had many to spread out the load and he kept them perfectly fed and in excellent health, then raised thier sexual energy and took that, not thier life force directly.
Modern day people don’t typically have that option, and modern “vampires” have not the foggiest idea what they are doing from an energy working perspective - they have no hope of understanding any of this because they’re so full of themselves as "imma predator 
" they don’t even think to learn.