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.
The title somewhat misrepresents the idea put forward.
It’s not that free will doesn’t exist in the Physics sense of superdeterminism.
It’s that we are all victims of circumstances such that people who do good things aren’t doing them out of some significant actual choice to do so nor do those who do bad things make a choice to do them, but that there’s only an illusion of choice as good people are circumstantially going to do the good thing and people who do bad things really had no viable other options given their combined neurology, psychology, and environment.
Physically free will very likely exists, as certain behaviors in our universe don’t make much sense if it doesn’t. But that’s separate from whether someone with a prefrontal cortex TBI is going to assault someone because they literally have no impulse control.