Mass shootings fail as galvanizing events for gun reform because opponents morally disengage

Evidence

It was widely assumed, especially among those favoring tougher gun laws, that the Newtown shooting would be the galvanizing event that finally forced polarized factions to find common ground for reasonable gun laws. … What came as a surprise was the swift, collective moral disengagement by progun proponents while the young victims were still being buried. Wayne LaPierre announced that the NRA would fight any legislative efforts to tighten gun laws (Stolberg & Kantor, 2013). — Albert Bandura, Moral Disengagement, 1245

Categorization

• XREF: Contradicts the naive ‘outrage forces change’ model of politics; echoes moral disengagement’s core claim that moral emotions can be detached from action.
• QUESTION: What conditions would actually make a mass shooting a galvanizing reform event? Does any historical case exist, or is moral disengagement structurally guaranteed?