Judaism asserts that evil exists in everyone, not to exclude the smallest child.
So evil is a part of our being.
But we must keep in mind that creation is not something complete.
If something is complete it has no way to go on.
Creation is something that goes from a certain point on.
So while evil is a part of our existence it doesn't mean that it should be like this.
There is a very, very old story about circumcision that deals with this same problem.
The Roman governor of Judea asked Rabbi Akiva, "If God wanted a person to be circumcised, why didn't he create him that way?"
And he answered, "If the Lord wanted, let us say, cakes, why did he not create them?"
He creates certain incomplete things and allows men to perfect them.
–Rabbi Adin Steinsaltz
From The Strife of the Spirit, p.225, by Rabbi Adin Steinsaltz