There is so much evil in the world because it is the devil who is doing it. The devil is the one who engineers people into doing what is offensive and evil.
God created a perfect world. The Bible records so. He made everything and observed that it was good. God is not an evil God. He does not do evil. He does good. He is a good God. He teaches us to do good. All of His plans for our lives are good. There is nothing which our God does which is not good.
When God created man, he created them for good works. He made man to be an agent of doing good in this world. But when the devil came in, he corrupted what God had made. From the moment that man heeded the instructions of the devil, the world changed from being a peaceful place to a place full with much evil.
God is not the one who allows all the evil we are seeing. It is the work of the devil through men.