You just moved the shaming from "look they are lazy and don't move from the couch" to "they are lazy because they made bad decisions"
You can fail to take action, you can take drugs to manage the negative situation more comfortably, but, if abuse is the underlying issue, a genuine change of circumstances is required.
However it can take a while to realize the problems and manage to get out. This may have effects that last for a good while. People do not deserve abuse or the negative effects of such abuse, just because they technically could have made a change, or made it earlier.
Sometimes, the outcome of one's decisions (bad is an unnecessary value statement here. Was it a "bad" idea to start a restaurant that failed and made you sad? Cmon).
However, a huge swath of mental illness, including depression, is the result of environmental and genetic factors utterly outside your control. Your mom smoked crack when you were in her womb and somehow that's "the outcome of your bad decision?"
Your brain chemistry is part of this will, though.
> science now knows that changing behavior is hard
I don't think science knows things. And while changing behaviour is hard, and much harder for some than others, it still doesn't mean that the total system that makes up your mind, including biological predispositions, is not your will.
But here's the thing, given enough knowledge that chemistry is deterministic.
Will seems to be one of those words we've created from deep ignorance, much like consciousness, and the more we learn about the world and ourselves the less our old views make sense.
What causes someone to suppress doing something they want to do, but have decided is wrong, even if they will never be caught? Or to do something they don't want to do, but have decided is right, even if no-one will ever know?
I would call that "will".
What is free will when you are suffering from pathological procrastination, depression or addiction ?
If you accept the fact that, like in addictions, your brain chemistry makes you smoke cigarettes or drink alcohol even when you know you’ll die from it and know it makes you miserable then how can you be convinced that you really control your normal behaviors ?
Why does anxiety makes me stay in my couch and antidepressants makes me want to go outside ?
I understand free will as a moral concept but at a biological level, i feel like it adds a lot of shaming and suffering to people who struggle to modify their behavior because science now knows that changing behavior is hard and impossible without physical modification of the brain structure.