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.
That’s true, I should have been more careful with my use of the word “rights.” What I meant regarding free will was whether or not they’d have all the same rights as a human. The Animal Welfare Act I think is a good example of where we convey a more limited set of rights to things which can experience pain, but don’t have free will*.