There's really no explaining it other than this story has a "girl next door" affluent suburban vibe to it. A lot of people have confused young women like this in their families or circle of friends so it hits home more than say, some inner city kid from a poor crime ridden neighborhood disappearing. That typically is not considered newsworthy.
Oh goodie,another Soap Opera thread
The new "Natalee Holloway", that's why Fox News used to be called, "The Missing White Girl Channel".