I oversimplified. Sweet cassava only needs to be boiled to get rid of the cyanide. Bitter casava needs to be soaked, boiled, cut up, and sun dried to be rid of the cyanide. Most people eat sweet cassava, but bitter cassava is still used because it is much more drought resistant. In places that don’t know to soak it long enough a disease called konzo can result and tens of thousands of cases happen every year. Even in places where it is processed more, tropical ataxic neuropathy can occur in old people.