Pumped Up Kicks is a popular song and Columbine plus other school shooting lore is popular among kids. It’s definitely a generation with PTSD over this. Dank memes about school shootings are, I think, part of a coping mechanism.
School shooting drills are a part of US schools since Columbine. That was 1999 It’s 2018. That’s a WHOLE generation raised with school shooting as an inevitability.