In this case it's based on a heuristic. I can't at all model human will so it seems reasonable to start with it as infinite (since it's so vast and appears virtually limitless, the very reason I can't model it in the first place) and model in the constraints.
edit: also, I am a Christian and that probably factors into my view subconsciously, although I am certain many non-Christian views would arrive to the same conclusion.
1) they are unsustainable (like harming allies) - not sure can be fixed
2) Don't have enough knowledge(broken perception) to do differently.
3) ROI of doing evil is too high.
etc.
Could you point to scenarios where aknowledging non-existence of free will could help us? IMO it doesn't matter.
EDIT: Actually I think that existence of concept of free will is positive because it makes people compute choices better (even assuming free will does't exists and computation is deterministic)
Short summary: I’m transgender and couldn’t transition when needed and to live a life of less pain because of others.
Arareness towards understanding people are who they are without any control brought me to realizing “who the best me would be” in the current situation. A person who cannot blame directly the person who wronged me. I might end my life by suicide though. So the impact of what others did to me was great and I still trumped it.