First, courts do hold manufacturers responsible for manufacturing or design defects.
Then, generally, "software is just a tool like a knife" doesn't hold because software today is more a service than a tangible good. Companies continue to update the programs and things can happen in the cloud with limited user control.
Then, generally, "software is just a tool like a knife" doesn't hold because software today is more a service than a tangible good. Companies continue to update the programs and things can happen in the cloud with limited user control.