You're assuming free will isn't some complex-looking behavior driven by quantum uncertainty. In the multiverse, every social scientist has many clones who's studies refute their work!

Even if that is so, a quantum description of human behavior is fairly useless in terms of practical application. How does knowledge of the standard model cure the infirm, prevent crime, and so forth?

When we exhibit behaviors. Our context is derived from our visual/auditory field processing from birth. Those waves implant magnetic field signatures on our neurotransmitter morphologies. We are almost explicitly operational in quantum activity. Many if not all disabilities or health complications are resonant to your mind body homeostasis. Challenge the quantum spectral development process of a person you solve the aforementioned issues.

Right, but how is this fact in any way helpful in dealing with the phenomenal world?

I'm not sure that we're arguing different positions.

The natural sciences, the so-called "hard sciences" are really the easy ones, because what they study doesn't have free will. The truly difficult sciences are of human behavior.