Since the Harvey Weinstein revelations, I've been thinking about the normalization of pathological behavior. This is a common phenomenon in our society and in most societies.
This article in The New York Times summarizes the reasons why women often don't report sexual harassment--mainly, that they fear retaliation. There are other factors, however, that make people in general turn a blind eye to harmful and pathological behaviors. These include psychological defense mechanisms such as denial, rationalization and dissociation, effects of mass culture, and deliberate propaganda by vested interests that uses rhetorical tricks to minimize atrocities. I'll address psychological defense mechanisms today.
Psychological defense mechanisms serve to ward off anxiety by distorting reality. In rationalization, the mind invents "reasons" why something happens that aren't really logical, but serve to distract from an unpleasant or frightening reality. In dissociation, consciousness is altered so that an experience isn't perceived at all in daily consciousness, but may be acted out unconsciously, or remembered while in an altered state (such as hypnosis). Denial is a phenomenon in which "the existence of unpleasant realities is disavowed; [it] refers to keeping out of conscious awareness any aspects of external reality that, if acknowledged, would produce anxiety" (Kaplan and Sadock, "Synopsis of Psychiatry," 2007 edition).
The mind resorts to defensive maneuvers in order to preserve physical health. Overwhelming stress can cause great damage to the body--altering hormones, damaging the immune system, interfering with sleep and worse. The survival instinct will undermine the mind's ability to accurately perceive reality in order to avoid the physically damaging effects of overwhelming fear.
People who have been victims of rape or other traumas not infrequently experience dissociation. Aspects of the trauma may be blocked from conscious awareness.
Sometimes trauma survivors invent "reasons" why the incident occurred (rationalization). As the general population is made aware of behavior such as Weinstein's, others may also engage in denial or rationalization. People don't want to believe that another human could be that horrible, and perhaps especially, when that human is the same gender as they are. It's too frightening.
The way to overcome denial, dissociation and rationalization is to speak about the crimes and traumas. Overwhelming evidence eventually destroys the use of distorting defense mechanisms, for most people.