Faith says that God is good and good is real.
It says that evil is a lack of a good that should be there.
It holds that evil is not real so there is no reason to ask how God could create it.
But the argument is pointless because God could deliberately set up a lack and still be evil.
While humans may lack good when they do harm deliberately, they also use good in a twisted direction. They abuse good things such as their intelligence, their feelings, resources to do harm with them.
The idea is that moral evil is always a lack but the distortion is built on that lack.
If God himself is distorting his own good how good is he?
If God is not to blame for the lack, he could still be taking advantage of it to get good distorted.
There is no evidence that evil is really just a lack or if it is something darker - an evil substance.
If evil is a lack in one case, that does not mean it cannot be a substance in another. Or some combination.
Evil is supposedly able to use our doubts and fears. The whole conversation about evil is riddled with guesses.
Paradoxically, the more one opposes evil the more one helps it. Where it is crushed one way it is nourished another.