Argument from evil, restated

[Godscreated]

Thought about this while listening to a debate when the concept of the atonement was brought up.

The argument from evil is usually: Evil exists, therefore a good god cannot. I'm going to make it backwards. Atheists, bear with me, I'm going to grant a lot of premises.

If any sin is committed, no matter how insignificant, it's all the same in the eyes of God, which is because he is sin-free, 100% good, and detests evil. Yet in Isaiah 45:7 it explicitly states that he created it, and indeed, if you believe that the tree of knowledge of good and evil existed, then the concept of evil existed prior to Adam choosing it.

The point is, why would a god who detests evil also create or allow it to exist in the first place? The correct answer is, he wouldn't, regardless of giving us free will.

This also brings into question the atonement, because there need be no retribution for god since the problem originated with him in the first place.

You are taking Isaiah 45:7 and using a wrong translation of the word used, in some translations the word is translated evil, the word evil does not even fit the wording of the verse.
Isaiah 45:7 The One forming light and creating darkness, causing well being (peace) and creating calamity; I am the LORD who does all these. NASB
Do you see how light and darkness fit with each other, so peace and calamity fit with each other, evil does not fit especially if you read the entire chapter. Even more so if you take into account what this book is telling us.
Now how can anyone explain how God being righteous could create evil. Evil is an action not a thing, God did not even create Love or Good, that is who God is, not what He tries to be or attained. So love and good have existed forever because God has always existed. For God to have created love and good He would have had to create Himself and God was not created, He has always been.
So where did evil come from if it was not created, others here have already explained it, going against God's will, disobedience. Lucifer brought this about, he is the perpetrator of evil, until Lucifer went against God's will there was no evil.
God did not create evil for it was not created it was simply done and evil then existed, so you can blame Lucifer for evil and sin, because they can only exist as long as someone is going against the will of God. It can and will disappear one day, it will leave as it came.