Free Will would finish God, not Atheists. Think about it.
1) God is omnipotent
2) God allows us to have free will
3) Free Will would mean, by implication, that God's will is not unbreakable, and therefore God is not Omnipotent.
4) The fact that God would allow people to continue to believe that he is omnipotent when he really isn't means that he is guilty of lying.
5) Satan is the father of Lies
6) God is Satan