Once upon a time, still back in my home country, one of my responsibilities was to participate in a team which was investigating child abuse. Mind you, it was in country where a few lashes or public berating a child was, and is, a totally acceptable norm. So, we were not about a kid screaming because he did not get one more candy. We were after parents who were on the murder's path.
The first thing I was taught there was to watch out for extremes, both ways. Families where kids were left with no food, water, heat and clothes while adults were drinking themselves into oblivion somewhere were just as dangerous as idyllic anclaves of prosperity and happiness. The latter ones were, in fact, more malignant. From those nestles of joy we took out children savagely beaten through blankets so that there were no bruises. Children starved almost to death so that they could become figure skating or gymnastics stars. Children allowed out from their rooms for 30 minutes every day (that included toilet, food and everything else) so that they could concentrate on their schoolwork. Girls who were seduced by their own fathers, with their mothers' blessings.
With no exclusion, all those monsters of parents started, and repeated, the same thing: it was done out of pure parental love. We wanted things better for children. We love them. Maybe, sometimes, we pushed a bit too hard, but we just wanted better, how is that wrong? When the cases went to Court, nobody ever believed that such loving, dedicated moms and dads could commit athrocious crimes toward their own children. Even after showing a pucture of a tiny, emaciated body of a girl who did not make it. The parents insisted on their total innocence, and went to jail with look of martyrs upon their faces. None of them ever showed any remorse.
Denial is an extremely powerful tool of human psychic. It is like a self-administered narcotic, bringing peace of mind and freedom from guilt. Just like only tiny minority of substance abusers ever come to realization of what they have done with their life and with those of others, the similarly tiny minority of abusers, sexual predators, sadists and other not-so-pleasant types of people would ever come to understanding of what havoc they inflicted upon themselves and others around them. They will develop thousands upon thousands of absolutely rational arguments of why they did, and doing so. They would plead their innocence to their last moment.
It is not only so about things which are illegal. One my nursing school mate is in her X+1 divorse because no man in the World seems to understand her female soul's wishes. According to her wishes, she needs at least a multi-billionaire even to begin with. Yet, she vehemently denies her own crying irrationality. Otherwise, she is, AFAIK, quite a competent nurse and an interesting woman.
Abuse can start, and continue, everywhere, given the right conditions. Basically, only two things unite someone who dirtily berates a new empoyee for a tiny misstep and the one who beats another helpless human being: perceived lack of punishment and rationalization of their actions. Where these two are able to apply these two conditions, they act. In all other situations, they have to stop and so become those charming ones. Or, at least, so totally "normal" ones that, when the facts came out to light, nobody believes them.
Nurses are not immune to anything pertaining to human society, being it good, bad or evil one. What described above, applies to them just like to everybody else, with a few peculiar differences, like nurses usually lack opportunity to act upon the real source of their frustration (aka unmanageable workloads, crazy families, rude doctors, etc), therefore, given the two conditions above, they lash out onto other nurses, with others conveniently looking other way. They also similarly tend to rationalize their actions, even absolutely abhorrent ones, with a convenient, all-size-fits-absolutely-all, argument that "it was only about patient care".
So, no surprises. Abusers are abusers, they only need right place, time, conditions and circumstances to act. And then they will blame the said place, time, conditions and circumstances. The gun fired by itself, he/she wanted it and even asked me for it, we were just having fun, that new nurse was breathing 0.658 times/min more than I wanted and that could negatively affect patient'care.