Appeal to legality. A similar argument could be made that this would be to stop mass shootings, meaning this bank ban on guns would fall under legal grounds, not moral grounds.
Sadly it can’t because gun manufacturers are legally not liable for shootings this has been argued in court.
Want that to happen change the law.
I'm not entirely sure they should be liable. A car manufacturer isn't liable if someone commits vehicular homicide, and McDonald's isn't liable if someone eats themselves to death with Big Macs.