Again, why should gun makers be liable for the wrongful, illegal use of guns when we don't apply that bizarre logic to any other product, even though more people are killed by hammers and clubs than are killed by rifles each year?
Using liberal logic, we should allow companies that make hammers and clubs to be sued by the families of people who are killed by hammers and clubs.
For that matter, if gun makers should be sued even for accidental, unintentional shootings, then auto makers should be sued for car accidents in which people are killed or injured.
Do you actually have proof that there are 30,000+ hammer deaths every year.
Gun makers should be sued because they market their product to people like Nancy Lanza, a crazy Prepper who was stocking up with guns like the Zombie Apocolypse was coming. Too bad she didn't keep an eye on the Zombie she was living with.
According to the FBI, more people are killed each year with hammers and clubs than with rifles. See:
FBI: More People Killed with Hammers, Clubs Each Year Than Rifles
Gun makers do not market their product to anyone who is unstable or evil, no more than auto makers market their product to people who intentionally run into other cars, who leave the scenes of accidents, etc., etc. That is erroneous logic.
Using your logic, beer producers should be sued because "they market their product" to people who intentionally drink and drive and who then go out and kill or injure other people.
Your argument requires the illogical assumption that if a company advertises its product and a few crazies misuse that product to harm others, then the company "marketed its product to crazy people who then used that product to harm others."