Maybe that is a requirement for some users, but it isn't a universal one. Plenty of people see a benefit in assistive technology that isn't complete such as adaptive cruise control or boilerplate/scaffolding dev tools.
It also raises the ethical question of whether these creators are responsible for the misuse of their products. Is it enough for them to say "This is how this product should be used. You are on your own if you use it outside these settings."? Holding developers responsible for the misuse of their software could create an actual slippery slope. Where is the line drawn? Do we start punishing people who create encryption algorithms because someone used the encryption to hide evidence of a crime?