It's not a theory. Evil is the absence of good.... I find it amazing that any Jew could believe that God was responsible or capable of creating evil.
God created everything. Your theory the absence of god (whatever this could be, because nothing is without god) creates evil, is not plausible. Again: When someone kills someone else then there are many factors in this "game". For example a weapon has to be produced, transported, dealed, sold, bought ... - a situation has to be created - a meeting arranged - and so on and so on - and then someone kills someone with a bullet. Nowhere is any absence of anything - except the absence of the respect for life. The whole evil system is wrongdoing - and not absence.
And again. God created the devil. And he knew before he created the devil what will happen. He knew also what Eve and her children will do. And so on.
If you want to believe that God created evil. Be my guest.