He's saying that just because the movements of particles are not predictable doesn't mean you all of a sudden get to claim "free will"-- the ability to somehow

He's saying that just because the movements of particles are not predictable doesn't mean you all of a sudden get to claim "free will"-- the ability to somehow impose an arbitrary desire in the chain of causality between your sense experiences and your actions. In order for you to have "free will" in this classical sense, you'd have to control the "slit" the electrons "swerve" through. But you don't. They just act randomly. They're not the things that impose your will. Your will is still an illusion.