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.
If you don’t know any math and I explain you why 1 + 1 = 2 and you get it, it’s not because you decided to understand. You helplessly did so and you can’t unlearn it anymore. There’s no free will in that.
This same applies to the judge and jury. If they truly understand the illusion of free will it will have an affect on how they relate to other people. You simply cannot blame them for their actions the same way once the illusion is broken. It’s like knowing the stove is hot and still touching it. You can do it but you’ll get burned and no matter of how hard you want to believe it’s cold it just isn’t and every attempt to live your life like it is just results in you getting burned again and again.
I think breaking the illusion would remove the concept of “blame” or vindictiveness from the judicial system, but not punishment. If a cog is broken in your watch, you remove it and get it fixed. You don’t remove it as punishment because the cog chose to misbehave, you do it because it’s necessary to get a fully working clock. Bringing it back to the court example, you put them in jail, not as punishment, but to protect society, rehabilitate, and/or set an example for others.