Free will is not popular just because it says our actions are our own. It is popular because of the consequence of owning and creating what you do - rewards and un-reward (punishment). Many care only about that. Maybe all do deep down. We all care perhaps up to a point. We cannot show that free will is treated as being about owning what you do and not that. We could be abusing the concept of free will as a means of carrot and stick. Nothing can take away that suspicion.

It is true we cannot condemn free will just because it is misused in such a cynical way even if everybody is misusing it.  But we can ask if such a belief is really useful or important when it bears such terrible fruit.

Most people keep up the lie that we are free agents because it gives them an excuse for wanting their pound of flesh and we all suffer from the conditioning of society and religion that makes us that vicious. People are eager to believe that what they are they have become through their own free choice. They may not realise it but it is true.
People also think that the threat of hate and condemnation frightens would-be criminals off crime. This shows concern for keeping order and not for what people are like inside. If you would commit a crime but cannot or are too scared to you are still bad. And if you threaten even implicitly you are no inspiration for those tempted to commit crime.
The fact that free willists avoid taking what is coming to them for their sins or crimes proves that they are only after the doctrine of free will for the rewards for themselves and to get persecuting criminals under the guise of punishing. This incorrigible and irreformable and permanent selfishness is another proof that there is no free will for free will presupposes the power to be selfish or unselfish. The selfishness is so prevalent that we must ask what use the doctrine of free will is and the answer we will come up with is none.

Religion that teaches there is an all-powerful God want to blame us not him for evil and suffering so they have the greatest need of all to promote the lie of free will.
If the doctrine of free will is a necessary evil for controlling bad people, then to make out it is a gift from God is going too far. For religion, it is a gift in the sense that it is a faculty or power we have from God. The other gift associated with it is the alleged revelation from God that we have free will thanks to him. For the believer, it is more important to believe in free will for God supposedly said we have it than to believe in it for any other reason. If you can only have one reason to believe then it is because God says we have free will.
Not every philosopher and thinker thinks you are the you you were when you were born or even ten years ago. They think each person gradually turns into another person. Christians invent the idea of spiritual soul to avoid that thought. The soul is supposed to be the same no matter what else changes so you are the same person all the time. The soul is an excuse for denying that John at 10 is the same person as John ten years later and ten years after that. It is an excuse because there is no evidence.

Personal identity and personal responsibility is the foundation of everything. But even if we have free will we have no right to reward and punish somebody who has changed a lot. Some people seem to turn into new persons faster than others.
Free will does not give believers what they mostly want. Thus the doctrine is only fit for discarding.
It is said by Christians that we chose the tendency to sin. With choosing sin we chose the natural consequences of evil: we chose death and suffering and stupidity. So considering the magnitude of suffering in the world we are accused of calling down and enabling terrible consequences when we sinned. But these things arise from a lack of free will not from free will. In what way? We think we will be lucky and the consequences will not be bad. We think if they are bad we will be able to remain reasonably okay or at peace. It is like the attitude that you will face suffering when it comes and are resolved not to let it get the better of you.
People say they punish you for doing wrong. In reality they punish you for the side-effects of what you have done. People never cry blood just because you killed somebody but because they see the suffering and fear that happened after it.
You are only fully to blame for the bad consequences if you see them and know they will happen and still do the bad deed. Nobody has ever really known and life teaches us that the unexpected can happen and good can do as much harm to you in terms of consequences than evil.

To argue that you can do something totally against the grain such as be a saint in reality and then murder implies you can make your will override everything and do something that is totally out of character without explanation. Free will when understood correctly refers to the power to self-create an act like that as if it were random. There is no explanation for what the person did only that they used their free will. Punishment is just vindictive if that is what we are like. Worrying about deterring others and reforming offenders would be an excuse for hurting them. The reason for believing God has nothing to do with what evil we wreak solidifies and reinforces and sanctions is free will which is a nasty and passive aggressive and bad doctrine. What reinforces bad must be even worse itself. There is no free will to turn free will into a good doctrine so it is rubbish. Worse we are told that anarchy will reign and evil will triumph if enough people start saying we don't have personal responsibility for we have no free will. That is a strawman argument and a lie. It is a harmful lie.
The doctrine of free will if it is to be believed should not be believed as lightly as it is. It has a dark side that is always there and at best is a necessary evil. It is an insult to its casualties to call it a gift from God. The demise of the doctrine should it prove to be false can only be a good thing.
Belief in free will is a crime itself. Wanting the doctrine to be true should be a crime!  Wanting God means wanting the free will doctrine so both should be a crime!

Why I Became an Atheist, John Loftus, Prometheus Books, New York, 2008
Baumeister, R. F. (2008). Free will in scientific psychology. Perspectives on Psychological Science, 3, 14-19.

Krueger, J. I. (2004). Experimental psychology cannot solve the problem of conscious will (yet we must try). Review of ‘The illusion of conscious will’ by Daniel M. Wegner. Behavioral and Brain Sciences, 27, 668-669.

Krueger, J. I. (2018). The drama of human exceptionalism. Review of ‘The human instinct: How we evolved to have reason, consciousness, and free will’ by Kenneth R. Miller. American Journal of Psychology. (link is external)

Searle, J. (2013). Our shared condition – consciousness. TED talk. (link is external)

Vohs, K.D., & Schooler, J. W. (2008). The value of believing in free will: Encouraging a belief in determinism increases cheating. Psychological Science, 19, 49-54.

Wegner, D. M. (2002). This illusion of conscious will. Cambridge, MA: MIT Press.