An unhinged lunatic shoots a (comparatively minor) government official because his hallucinations made it make sense, he proceeds to fire randomly into the crowd because "oh right, unhinged lunatic." Another (minor) government official is hit and killed, as are five other people, one of them a child. When people list it out, they mention the congresswoman (who's still alive, last I heard; correct me if I'm wrong there), then the child, commenting on how tragic the child part is, and proceeding to ignore everyone else. Of the people killed, the child is the least important one.
"Hopes and dreams"? Those aren't, you know, actually worth anything. At all. Ever. You might as well be mourning that she died with such a diminutive stature, and could have totally grown another couple of feet or so.
As I said, the only reasons to single out the kid are either a foolish kneejerk reaction ("OMG A KID SO TRAGIC YOU GUYS"), bullshit sensationalist journalism ("HEY EVERYBODY, A KID TOTALLY DIED AND SHIT AND THAT'S JUST HORRIBLE PLEASE LISTEN TO US TALKING ABOUT IT BECAUSE TRAGEDY (AND RATINGS)!"), or people who feel they'd be singled out if they didn't pay lip service to it, I presume (the previous reason could also end up under this, since it would "look bad" for journalists not to be spewing disingenuous commentary on "how bad it totally hurts them inside, because a kid you guys a kid"). Unless you personally knew the kid/their family, and none of the others, where it's an understandable sentiment, due to proximity making that particular part more personal than the rest.
And yes, if you go out of your way to try to empathize with the kid or their family to a rather unhealthy degree, you'll feel sad on a personal level about it. It's unhealthy to do so, because it serves no purpose but feeling agony. It's generally involuntary when a matter is actually personal, where the appearance of empathy, and the support it may compel you to provide, are important social mechanisms. Getting all bent out of shape because a kid thousands of miles away died (who isn't connected to you at all)? Not conducive to a healthy mind in the least.
Maybe it's just when I see the headlines "plane crash kills 8" and "crazed killer murders 8" I tend to think they're the same, more or less... Regardless of how innocent the victims.
Honestly, if I saw "plane crash kills 8," I'd marvel at how few casualties there were
for a fucking plane crash. Unless it was accompanied by a picture of a wrecked cessna sticking out of a house or something, which would make it disturbing that a two man (correct? or do they hold more?) plane also managed to kill another six people by falling out of the sky.