What always amuses me about the "bad apple" defense is that in many situations I would imagine that if you objectively looked at the size of an organization vs the number of people involved in scandals over the years, it's not just a couple of bad apples but quite the opposite - say a statistically significant higher rate of xxx crime or behavior vs the general population.
I would imagine this happens by itself really: once something like corruption/bullying/sadism becomes established enough in any small or large institution, it tends to drive people with a conscience away (instead of attracting them to where they are most desperately needed) - where that doesn't happen actively, that is, as a sort of self-defense against likely snitches. So over time, left unchecked, it just compounds.
