"Energetic vampirism" is one way to describe the main way the jewish soul generates energy, by siphoning it from other things (another would be to receive it from their "god", the hivemind they worship and work with), which can theoretically also be done by a Gentile soul, as certain barbaric tribes had done in the past with the use of blood Rituals.
However, the way this operates is through taking energy from a soul that can infinitely, naturally, generate it. Obviously, one can't siphon energy from a soul that is also designed to siphon energy. Or, at the very least, it would be inefficient and dangerous.