Why is free will so important to so many people? Why idolize something that God would not be in control of? In fact, this libertarian freedom you always speak of is impossible, no one has it, not even God because He must always act according to His nature! All is determined!
Seems to me anyone can see how free will could become an idol. Why would you choose to worship an idol?
Your question is absurd if not ultimately self-defeating. For it assumes only two possibilities: the first is that God has causally determined my thoughts and beliefs in such a manner that it is impossible for me to think or believe otherwise. If this is the case, then the answer to your question is the following: Because God causally determined me to “worship free will as an idol.”
If that is the case, do not blame me for worshipping idols. . . blame God!
Or perhaps the answer is found in that God has created mankind in His image (“likeness”) and given man limited libertarian freedom (the ability) to choose between a range of options, each of which is consistent with our natures. Given this libertarian freedom, perhaps I have freely chosen to “idolize” free will although I could have done otherwise (or at least nothing caused me to do so). If the latter is the case, then I possess libertarian freedom and can freely choose to “worship it.” Be that as it may, libertarian free will still exists. Pick your poison (if you have a choice): I am either ultimately caused and determined to “worship free will” (and I am not responsible) or I have freely chosen to “worship free will.”
You said, //In fact, this libertarian freedom you always speak of is impossible, no one has it, not even God because He must always act according to His nature!//
Before going any further, consider God’s perfect nature. God is a maximally great being and thus, God’s nature is perfect LOVE (omnibenevolence), perfect POWER (omnipotence), and perfect KNOWLEDGE (omniscience). I have argued that the Molinist position is the only view of God’s sovereignty that can logically make sense of each of God’s Big 3 omni-attributes. Here is a slightly different version of the Omni Argument supporting my contention:
1- If divine determinism is true, then, given God’s omnipotence and omniscience, if God wants all people to go to heaven, then all people go to heaven.
2- Not all people go to heaven.
3- Therefore, given God’s omnipotence and omniscience, if God wants all people to go to heaven, then divine determinism is false.
4- If God is all-loving (omnibenevolent), then God wants all people to go to heaven.
5- God is all loving.
6- Therefore, God wants all people to go to heaven.
7- Therefore, divine determinism is false.
8- God is completely sovereign and predestines all things.
9- Therefore, divine predestination and divine determinism are not to be conflated.
10- The best explanation of the data is Molinism.
So, given a Maximally Great Being’s omni attributes, there are several options from which God can choose that are all equal and consistent with His maximal nature. For example, God could have chosen not to create at all, or He could choose to create. This is an example of libertarian freedom. If you are going to say that God HAD to create humanity, then you will be forced to ultimately affirm the heresy that God was lacking in glory apart from humanity.
Moreover, if God is not free to choose between a range of options consistent within His nature, then He is not omnipotent. Your position destroys “all-potency,” and replaces it with “uni-potency.” My view is that God has the power — and freedom — to do ALL possible things. Your view is that God can ultimately only do one thing and He has no ability to do otherwise. On your view, God has no real choice in the matter.
On top of that, not only is your view a minority position, if your view did happen to be true, then prepare for modal collapse, fatalism, and the necessary existence of humanity — putting humans on par with God (blasphemy)! Your view paints God (or should I say “god”) as a weak, impotent, and needy being. I would rather affirm Molinism as it shows God for who He really is: a Maximally Great Being!
John D. Laing makes it clear:
If [God] had to create, then in some ways he is dependent upon the creation. Under Theological Fatalism, we all become necessary beings of sorts. Second, Theological Fatalism is based on the false idea that God’s obligation to do the best limits him to only one option. . . there could be several equally good options which are the best way for God to achieve his desired ends. (Laing; Middle Knowledge: Human Freedom In Divine Sovereignty; 2018; 32)
Bottom line: The word omnipotent really speaks to God’s libertarian freedom. It means that God has the power to do ALL things (even the things God never chooses to actually do). This is seemingly infinite libertarian freedom! However, if humans are created in the image of God, then it stands to reason that humans can possess limited libertarian freedom (simply pointing out an aspect of reality should not be confused with worship).
It amazes me that some resort to detracting from God’s omni-attributes just to keep their personal view of divine determinism in tact. Talk about the pot calling the kettle black — that is the epitome of idolatry.
Stay reasonable (Acts 17:2),
 This is a summarized version of a longer objection I received on social media (along with other Molinists). I have heard similar claims in the past and thought it prudent to address this question here.
 This is a summarized point of response from Eric Hernandez.