Before epilepsy was understood to be a neurological condition, people believed it was caused by the moon, or by phlegm in the brain. They condemned seizures as evidence of witchcraft or demonic possession, and killed or castrated sufferers to prevent them from passing tainted blood to a new generation.
I feel like the level of mass education about the lack of free will required to make sure all judges and juries understand that murderers have no free will, would probably end up educating a lot of people with violent tendencies that they have no free will too - and if free will does exist, they now have an excuse not to even try to control themselves. Which the article did note has been observed in other studies.