heani, taking energy to survive is not evil. That would be like saying if we eat anything (because even veggies are technically alive to some degree and defiantly have energy) to survive, we must be evil.
We take energy all the time from various sources for various reasons. When some people cast spells, they use the energy from herbs, crystals, candles, the elements, the moon, their deity, ect.
To take energy because you are not capable of replenishing your own to the degree you need is simply survival and survival is natural.
To do it for kicks and giggles, well..to each their own.