Free will and you.

[Aroura]

Long term studies on people who actively disbelieve in free will have not been done. However, considering humanists and other such groups, it seems more compassion for others is a possible outcome

Not true.  Humanism, by definition, must include free will (and exclude determinism)

Wikipedia

    Humanism is a philosophical and ethical stance that emphasizes the value and agency of human beings

so being humanistic requires your own agency

I'm a humanist, and don't believe in most definitions of free will. Pretty sure you don't have to ascribe to the definitions in Wikipedia to join a group. The humanist group I belong to seems to have people with a mixture of stances on this subject, but most are some level of deterministic and would define agency as actions, not free actions. At most a few call themselves compatabalists, but none of them would describe agency as the ability to act, not the ability to freely chose actions. Even the dictionary only defines it as the ability to act, nothinges about freely closing actions.

I do understand that many people mean not free but just will when using this term. But that seems meaningless to me. You are determined to pick chocolate ice cream, but no one is holding a gun to your head at the time. This definition seems semantics to me as there is still no choice, you are determined to pick chocolate just as if a gun were to your head. You are still constrained by outside and internal forces, they just aren't as obvious or unpleasant, usually anyway, as a gun to your head.