Because that's what you WANT to notice. Did you hear about the woman who protected herself and her children by shooting an intruder breaking into her home? There are many news articles of people using a weapon to protect themselves or foiling a robbery if you would just bother to look.Yay! Another school shooting today! Gooooooooo guns!
In my informal survey of media coverage, I have noticed that the ratio of "Man uses licensed firearm to fend off would be intruder" to "Innocent person(s) killed for no damn good reason" articles is quite low.
This is what we call "ignorance" on your part.