It’s a slippery slope to charge the parents of a child for a crime the child committed.
What about teens who kill people with a vehicle bought with daddy’s money? I could argue very few teens are responsible enough to drive, and the parents know it. It’s a terrible situation, but unless the parent encouraged the boy to shoot up the school, I wouldn’t say they’re criminally responsible.
To the bigger issue, I think they’re going after white parents who legally purchase guns.
How many teens shot someone in a major city last night? Several I’m sure, all with stole guns.