> But we do sue American gun makers for deaths caused by lunatics.

No we don't, there's a federal law explicitly protecting gun manufacturers from liability for gun crime. https://en.wikipedia.org/wiki/Protection_of_Lawful_Commerce_...

Most of those examples have to do with the manufacturers knowing that their products were dangerous, addictive or illegal and advertising them aggressively as safe. They're mostly litigated on product liability claims. Banks are regulated by an entire architecture of laws, and we could enact laws that would regulate Flock too, as one of the other commenters pointed out they're doing in Oregon.