killers

How come crazy people have to take medication and serial killers do not have to take medication?

Because they like to Drug the normals and keep the cats free to preen their paws.

I’d be wary about suggesting anyone should have to take medicine. If someone doesn’t want to they shouldn’t have to - though if they’re a danger to society they should be removed from it, just not drugged against their wills.

Trivial answer.

Not all crazy people have to take medication, there are different kinds of crazy.
Crazy isn’t a useful medical term.
Crazy might mean mentally ill. That would include a whole range of illnesses, many of which are not treated with medication, or have no known treatment.
Crazy might mean schizophrenic, - it often does. Some schizophrenic people do need medication to stay stable. Not all do, and medication does not help everyone.

Not all schizophrenic people are serial killers, almost all are not.
Not all serial killers are schizophrenic, indeed most are not.

Some serial killers may be classed as sociopaths. That isn’t a medical condition as such, and there isn’t a treatment or medication.

Because once someone is known as a serial killer, society deems them fit for prison or death, not medication. Crazy people who have not yet killed or hurt anyone are generally given medication instead.

Because there’s no medication for serial killers.