The necessity for our free will is to keep GOD at arm's length from the creation of evil and to make those who sin truly guilty before GOD.
The Bible indicates very often that we are enslaved to sin's addictive power and so our free will is non-existent on earth.
By rejecting that we had a time of free will pre-sin while we were ingenuously innocent pre-earth, Calvinists are force to accept that because we have no free will on earth that GOD must decree our fall, which is a blasphemy against HIS good name as loving and holy and which they struggle to defend without impugning GOD's holy character but with little success.
By rejecting that we had a time of free will pre-sin while we were ingenuously innocent pre-earth, to support the necessity of our free will, the Arminians have chosen to reject that we do not have a free will on earth so they make our free will decision to seek GOD to be the answer to HIS call to salvation, ignoring the verses that stipulate against this and the fact that it leads inevitable to universal salvation which every mention of hell mitigates against.
By rejecting that we had a time of free will pre-sin while we were ingenuously innocent pre-earth, each of the big 3, Calvinism, Arminianism and Catholicism, are forced to believe that the righteous and holy GOD creates evil people in sin by placing us in Adam rather than as independent from him and putting us under his sin without any choice on our part as if HE needed sinners in HIS creation for some reason.
If you start with the true belief (not just lip service) in GOD's holiness meaning HE will not ever create anything evil which necessitates that all evil was creature created by their free will, then the supports for our pre-conception existence in the bible take on a different implication and cannot be so readily passed over in favour of the created on earth bias.
Peace, Ted