Charging the Crumbleys is unlikely to deter anyone or to prevent other shootings. The only reason to punish the Crumbleys is to punish them. Two more individuals can be held up to public scrutiny so everyone else can ignore the system.
Criminal justice in America generally focuses on punishment rather than on prevention or harm reduction. The right, in particular, is eager to fund prisons and police, and reluctant to fund or promote investments in the social safety net, mental health resources, lead abatement, or expanded healthcare coverage. Their stubborn refusal to countenance restrictions on gun manufacturers or background checks, or even to acknowledge that high rates of gun ownership create a dangerous potential for violence, is of a piece.
In this case, the right’s gun obsession trumps its rage for incarceration. But that oddity shouldn’t eclipse the glum truth that whether or not the Crumbleys are convicted, anyone who cares about reducing gun violence has already lost. Hopefully at some point progressives can gather the political strength needed to put in place gun reforms that will lead to less injury and less death. But charging the Crumbleys isn’t going to do it.