It is that Calvinism starts out with Unconditional election then builds it theology around that, that makes it impossible for man to have a choice.
God is omnipotent and can easily give man the ability to choose to accept or reject Him.
He talks with spiritually dead people (Gen.4, 20, Acts.10,) and they understand Him.
But allowing a choice, is something that the Calvinist maintains is beyond God's power?
No, you believe it is not God's will to do so, a 'will' that you maintain is a secret one and thus 'inscruptiable'.
Yet, you build an entire theological structure around a 'will' that is not revealed in Scripture.