The free will defence is the most unassailable answer to the "problem" of evil. Evil can exist without God creating it because we freely choose to commit it. But unbelievers have answers to this. One such answer is that even if God does not directly cause evil, He must still be responsible because He is the ultimate cause of all things. He created us with choice knowing we would often choose evil, therefore restoring culpability to Him.
But this is highly flawed logic. To illustrate this, let us consider a car crash. Every car manufacturer knows that there is a risk of car crashes. In fact, cars are specifically designed with safety features to minimise the damage caused by such crashes. Crumple zones, air bags, seat belts, and more, are all designed to reduce the chances of death or injury from a car crash. Manufacturers know the risk. Are they therefore responsible when these crashes happen?
The obvious answer is no. Car manufacturers are not making cars with the intent that they crash, they make cars with the intent of increasing ease of travel (and, of course, profiting from that). The intent is to make a good car, the result is the existence of a good car. Responsibility for that car, of course assuming it has been responsibly made, transfers to the owner as soon as the car is sold. The owner could skip a red light and smash right into the back of a police car 5 minutes after leaving the shop, the manufacturer has no responsibility for that crash, even though they are the ultimate cause.
We could go one step further and talk about giving birth. When a couple produce a child, they know only one thing for certain: The child will die. They do not know what the child will become, except worm food. Is that couple therefore responsible for murder? They knew the child would die if they produced it, they produced it anyway, but it takes a special kind of lunatic to charge parents with murder, unless of course the parents were directly and intentionally responsible for the death.
If it is absurd to charge parents with murder for the sole reason of knowingly producing a child they knew would die, it is infinitely more ridiculous to charge God with any evil. A parent knows their child will live, then die, but God knows His children will die, then live. The good and the bad are in opposite orders.
But what about those who will not be His children? God knows who will be saved, but He also knows many will be condemned. There are two things to consider here, the first being that condemnation is not actually evil. When someone does a bad thing and is condemned, that is 100% their fault, and is actually good. If Jesus never went to the cross and each of us was guaranteed eternal torment after death, that would be perfect justice, and no one could complain against God for that.
The second thing to consider is the choices that lead to condemnation. The responsibility for evil, ultimately, lies on the shoulders of the last free willed being with causal power. Just as the aforementioned car manufacturers seek to make a good car, so also is free will a good thing. It adds legitimacy to moral choices, and even relationships. Once free will has been given to us, we become responsible for our own choices. That includes whether or not we go to Hell. No one in Hell is there because God felt sadistic. They are there because they not only chose to do evil, but even refused to accept the free gift of salvation for it.
Although God is the ultimate cause of all effects, He is in no way responsible for evil. Evil itself is a corruption of that which is good. Murder is only possible because life, a good thing, has been created. Sex crimes are only possible because God blessed us with the institution of marriage. Theft is only possible because good rewards are reaped by those who work for them. Evil cannot exist without good, but good can exist without evil. Evil cannot exist without free will, but free will is a good thing, given to us to allow us to enjoy a real relationship with the God who gave us life. Only if you first say something as stupid as "we should prosecute parents for conceiving children knowing they will die" can you sustain the idea that God is, in any way, responsible for the evils we choose to commit.