Good and evil are opposites, like warm and cold, up and down, big and small. One extreme cannot exist without the other. You like good, right? Well, good cannot exist without the existence of evil. That is a natural consequence of our human reality. Can you have "hot" without "cold?" No, you cannot, because hot is defined by its relationship with cold. "Cold" is what give "hot" its meaning. Similarly, "evil" is that gives meaning to "good." God cannot abolish evil without simultaneously abolishing good. And if God abolished both good and evil, he would be abolishing our entire reality.