The free will argument demonstrates that christians don't understand free will.

[xpastor]

The Christian argument that God allows evil in order to give us free will only became prominent in fairly modern times as a supposed argument against atheistic determinism (i.e. a mechanistic universe in which all our thoughts and decisions are wholly conditioned by prior events).

However, Christianity itself has a long history of determinism. If God is omniscient and has perfect foreknowledge, then as our creator he has already foreordained every decision we make. Extreme Calvinism is the only logical form of Christianity: that from all eternity God has elected some to salvation and many to damnation, quite apart from anything they do.

As always, the bible is all over the place on the subject. There are plenty of text which strongly imply free will, e.g. God does not desire the death of a sinner, but that he should turn and live. Equally, there are texts which deny free will. The example of God "hardening the pharaoh's heart" has already been mentioned. In Romans 9 echoing a passage from Isaiah Paul compares God to a potter and humans to the vessels he shapes:

16 So then, everything depends, not on what we humans want or do, but only on God's mercy. 17 (G)For the scripture says to the king of Egypt, “I made you king in order to use you to show my power and to spread my fame over the whole world.” 18 So then, God has mercy on anyone he wishes, and he makes stubborn anyone he wishes.
19 But one of you will say to me, “If this is so, how can God find fault with anyone? Who can resist God's will?” 20 (H)But who are you, my friend, to talk back to God? A clay pot does not ask the man who made it, “Why did you make me like this?” 21 (I)After all, the man who makes the pots has the right to use the clay as he wishes, and to make two pots from the same lump of clay, one for special occasions and the other for ordinary use.
22 (J)And the same is true of what God has done. He wanted to show his anger and to make his power known. But he was very patient in enduring those who were the objects of his anger, who were doomed to destruction. 23 And he also wanted to reveal his abundant glory, which was poured out on us who are the objects of his mercy, those of us whom he has prepared to receive his glory.

This is pure Calvinist predestination. Many could not stomach the horrible doctrine (like Pelagius who argued vehemently for free will) but Augustine upheld the orthodox view.

So, to respond to the OP. Yeah, Christians are clueless on the subject of free will.