I think saying "mental illness" broadly is a problem.

I think being very specific in referring to what drives people to shooting: "Being socially alienated, bullied, told that manhood was being 'tough' and aggressive since youth, glorification of two inherently violent institutions (police + the military), prominent racism within society, being in a hyper individualistic society, and dare I say it violence in media all contribute to the level of violence in the US."

Every case is different, but I do think there needs to be more conversations about the social causes of gun violence rather than a knee jerk, short lived "debate" on gun control anytime something like this happens.