The vast majority of people are aware of when somebody has their wiring so messed up as to present a hazard to their lives. That is, we KNOW.
Although sometimes, the freak with the messed-up wiring is
really good at hiding their defect. 
I think that's what happened in this instance. At least we can be thankful this freak didn't kill that young girl.
In the hideous and unusual instances where a crime like this happens, it gets lots of MEDIA ATTENTION, and makes the weak-minded portion of our society
even more afraid than they were before...and that's pretty darn fearful, let me tell you!
My point is, in most cases, people who open their arms to other people, well, it works out just fine for all concerned.