What does a white person use for target practice? A public school.
Why would you joke about that? Do you consider this funny?
Because it's freaking hilarious. Public schools need to be put in their place, who do they think they are.
School shootings are always a tragedy, and it's never right to joke about them and paint white people in a bad light. Every school shooting joke and threat is taken seriously, to make sure everyone is safe. No student deserves to dread and be fearful of going to school. Your jokes can trigger bad memories.