Our culture is a patriarchal dominance hierarchy (as are most, but not all of the world's cultures today). Rape is an act of aggression and domination, as is garden variety bullying. If we didn't live in a dominance-obsessed culture, it would be a lot more likely that we'd treat each other with caring and respect, but as it stands we've been taught that if you don't "win" you "lose" which means you'd better make sure the other person loses. Everyone is your competitor for place in the pecking order, which means you can't afford to care too much about them. It's insidious and very dysfunctional.
"A dominance hierarchy (which is what patriarchy actually is, not just a dynamic between men and women) is about maintaining traditional power through displays of aggression, coercion, and artificial barriers to true competition. Police brutality is a symptom of living in this sort of system, as is sexual harassment and violence against gay and trans people. Those are all examples of using violence to dominate others who are seen to be lower down the pecking order.
Our social system revolves around clawing your way to as high in the pecking order as you can get, by any means necessary, including violently holding other people down or erecting barriers to them being able to compete — all the while telling yourself that you’ve earned your place fair and square."
And as you've said, even within more positive cultures, problems exist, and some individuals are dysfunctional, but at least in a culture that doesn't glorify that and view it as a being a leader of some sort, it's easier to identify and censure them.
