I think it's important to distinguish that these aren't people who are necessarily assholes to everyone. They have plenty of friends and acquaintances who would never believe they'd do something like this. And others who upon hearing it, would've assumed it was a harmless misunderstanding.
I think one of the larger problems that society is struggling with is the idea that two different people can be in very similar proximity, interact with the same people and yet one can have to suffer through radically different (and horrible) treatment.
The reason I believe this is so difficult, is the other person legitimately think "I know that person, I know that place, I've gone through that and I've never seen anything remotely close to that." And reasonably conclude that it didn't happen. It's difficult to accept that there is an entire world that they don't ever experience.
But we all need a find a way to account for this, because too many people go through beimg mistreated and their concerns are simply dismissed.