The story is just an absurdist fantasy and is not to be taken too seriously.
However, with that being said, I think that the existence of good does not excuse the existence of evil.
Evil — or, at least, what we perceive as evil — is not something separate from the universe, but an intrinsic part of it. And if you create a universe, you are not only responsible for all the good in it, but also all the bad, the evil, the horrible.
In other words, the inventor of bread and the inventor of something that spoils it are indeed two sides of the same coin, since the latter could not exist without the former.