This present Age is waiting on hold for theSecond Coming of Jesus, as God allows things to happen due to this being still a sin cursed earth, but when Jesus returns, that is all undone, and God will have exact reign on arth as now in Heaven!Good question....
I say God allows...But there's a reason.
At the fallen Adam brought the human race under Satan's rule. Paul calls Satan "the god of this world" 2 Corinthians 4:4 and Jesus calls him, "the ruler of this world" John 14:30 Hence our, fallen world is based on his system of iniquity and not God's agape. Satan's rule is based on the principle of "for by whom a person is overcome, by him also he is brought into bondage." 2 Peter 2:19
However in order to understand why God allowed Lucifer to develop his system of self-love, which contradicts God's agape love, we must go back to the creation of Lucifer.
God permits Satan tp do evil now, but still on His leash, and God will be righing all accounts one day!