Why would God do that?
To paraphrase Pascal, "God has His reasons that reason knows nothing of."
Whether you ultimately believe it or not, your question about my comments contains the presupposition that God exists.
Specifically, my comments refer to the God of the Christian Bible. Now, either this God exists or not. But remember, the context of our discussion assumes God exists; we are not arguing the question of divine existence, but the nature of God’s will.
To have this discussion, we both must have adequate knowledge and understanding of the Bible. I assume you would not refute this basic convention of intellectual dialogue.
The Christian God is known by Christian doctrine to have a Divine will and plan. The Bible teaches that God allows the prince of this world to have limited powers at specific times, according to God’s will.
As you can see, the answer to your question is that it is God’s will.
Again—when discussing these things we must think clearly. This will help us to distinguish and to focus separately on different matters. Oftentimes, the human mind becomes confused between questions pertaining to Divine existence and questions about the nature of God’s will. This sort of confusion hinders the pursuit of truth.