What do you mean by “responsible for their actions?” If a machine is faulty, we don’t absolve it of blame for creating sub-optimal output conditions. If a person murders someone else, the murder still happened and they still committed it. We would still react deterministically to this event, whether by demanding capital punish enemy, imprisonment, or rehabilitation. You then can look at the conditions this murderer emerged in and see if patterns emerge. If mitigating those environmental conditions reduces the occurrences of murder, then what other conclusion could you draw?

That doesn’t even go into the myriad of data that decision making processes occur prior to conscious recognition of the decision. That is, fMRI data highly indicates that the “sub-conscious” structures of our brain make decisions and then what we call our “consciousness” is informed about it.

Then you have the fact that chemical and physical alterations to our brain structure cause behavioral and psychological changes to a person. For instance, chemical hemisphere separation creates two personalities with two narratives. If a blinder is used, and the one hand gives the other hand something, when prompted the person will make up a story about how they received it. Without separation, the person says they handed it to themselves.

Once you look at things beyond individual decisions, it becomes pretty clear that there’s nothing special about the human brain that could possibly separate it from natural determinism. There’s no “soul” to override our physical brains.