The clickbaityness doesn't surprise me or even particularly bother me, since news headlines sent out as tweets are, like headlines themselves, intended to be "clickbaity" enough to get you to read the article in the first place.
What bugs me is "the reason why will shock you." No, CNN. The fact that it happened at all is the "shocking" part. Feeling unappreciated is just one of several non-shocking reasons why a teenager might lash out. If she stabbed her sister once to see if she'd deflate and fly around the room like an untied balloon, and 39 times more in order to make a more pleasing symmetrical pattern of cuts, maybe that reason would be shocking.
But as it is, violent teenage sororicide, regardless of motive, is shocking.
What a weird thing for me to get all pedantic about.