Prejudice isn't something you're born with, it's something you learn.
Yes--but then, so is a healthy respect for fire and other pain-avoidance traits.
I'm afraid to drive through Woodstown. It's a small town, but I've had three cars bread down within its confines, never to run again. That's something of an irrational fear, and it's not that strong, but I do recognize when I am in Woodstown that it's a place where I keep losing vehicles. The distortion in the random events causes me to feel that way.
There is a degree to which a lot of violent crimes are committed by "crazy" people. Most of them are not psychotic but sociopathic--but in the lay mind, that may be too fine a distinction. Besides, we would rather believe that the truly violent crimes (e.g., Columbine) are committed by people who are "crazy", because it gives us some basis on which to believe that the "sane" people constantly around us would never do that and so are not dangerous. The backlash of this belief is that should we happen to encounter anyone who is "crazy", we lose our assurance: this person is not "normal", and so cannot be expected to act and react in a "normal" way, and that makes them "unpredictable" in a way that is outside the normal parameters of human unpredictability. That unpredictablility in turn makes them "dangerous": we do not know what they might do, and so we cannot be certain they will not do something harmful.
The little girl has not yet learned that some people are dangerous. Her parents (commendably) did not teach her that the "crazy" person living in that other apartment might be dangerous, and she had no reason to think that you would be. In fact, she probably had no reason to believe that anyone might be dangerous--the adults in her life are not merely safe but a haven of protection from danger.
The man next door is different. He has reason to believe that other people, even "normal" people, are dangerous. That you are "not normal" amplifies that.
--M. J. Young