If a robot went around killing people with an axe, we would stop it and dismantle it. We wouldn't shrug out shoulders and say "The robot can't help it so we can't hold it accountable for what it's doing."
If an individual does something to break the law, we hold that individual accountable for it. There are tons of modifiers, maybe the individual was under the influence of drugs, maybe the individual was mentally challenged, etc. These things modify how we hold the individual accountable.
Now, since we have cleared out what a "choice" is and there is no more argument about that, it is easy to show that frontal cortex output is determined by input that are prior experience (or electrical signals coming in), genetics (how it reacts to them and how it is initially wired) and chemical environment (drugs/hormones/others). So there's no room for any kind of free will.
So as you see there is no conflict between lack of free will and morals/ethics. We just need to accept that your frontal cortex is "YOU" and if it produced defective output (a crime for example), it has to be punished regardless of predetermination to do so. And accept that it is ETHICAL and MORAL to do that. That is all.