I've often wondered myself how people can possibly do such horrible things to each other. There are just a lot of sick people out there, so much in tune with looking out for #1 and giving into their own selfish desires that they pay no attention to the ramifications of other people. Let me see if I can explain this right. It's really hard to keep from falling into the trap of thinking, "I'm me, and the other people around me are just other people." It's easy to think this subconsciously since being you is the only thing you know how to do. And it's easy to forget that the person standing next to you has the same types of feelings and emotions that you do, and that he is the "me" of his own world. Even so (if that made any sense to anybody), I don't see how anyone could get disconnected with other people to the point where they could perform such sick acts. The only explanation is that they simply choose to block out everyone but themselves as deserving of compassion and possessive of feeling.
In answer to your question, though, I don't think most people are near that point where they simply choose to cut people off so much that they feel no remorse when they perform such grotesque acts. At least, I'd like to hope so...
I'd just like to close by reminding everyone to remember that you're not the only "me" in the world. Everyone is the center of his/her own universe, and through that person's eyes, you aren't the center. You could be just another person. Try to think of things through other people's perspectives, not just through your own universe.