I mean, Adalind is really scared of her powers coming back, and what she did to that addict's fingers was weird, because if it was just a burst of random power she could have stopped him, or throw him across the room, or even make his head explote, but first she stopped him and then broke his fingers one by one, and for that you have to know what you are doing, and be cruel enough, it's not something that just happens. If her powers just made her empathy go away it could explain some of the things that she did, but she is afraid of going back to that path again, even if she knows better now, like it will make her go evil. It could explain what happened to juliette as well, instead of just not caring about others she wanted to hurt them, driven by some dark impulse. This theory would also explain why older hexenbiest are good, or just nicer but they don't have such harmful ideas and are more powerful, they managed to subdue the spirit, and instead of whispering to their ears to make them go evil they obey the hexenbiests and lend them their powers.