I understand that - I believe that the overwhelming majority of even those people who need help for being dangerous are a danger to themselves (at worst a person or two in the immediate vicinity) more than anything else. The amount of pre-planning involved in most mass shootings put them outside the purview of what most people are talking about when the bring up mental health.
Still, bringing down suicides is a worthwhile goal. But to combat what happened in El Paso and Dayton we need to address white nationalism. And look at what other countries with high gun ownership rates do to keep the violence down.