We must know evil to know good
Why does God allow evil? I believe that in order to know what is good you must know what evil is. How would you know what is good without knowing what’s bad? You would have nothing to contrast good to so therefore nothing can be considered good. Here is the best argument I have for this position.
A child who was fed and taken care of their entire childhood would not think that this is good — they just expect it. To them it’s a part of life, their parents take care of them and give them all they need and is neither good nor bad. It isn’t until they see other children neglected, or see other parents struggling to feed their own children that they come to the realization of what they had was good. Therefore we wouldn’t know what was good without knowing what was evil.
Also, let’s say a person intentionally murdered a child — that is evil. However, a loving God gave us freewill, therefore a loving God must allow that person to exercise their freewill and murder that child.