Hey, FTD: sidestepping the discussion of whether Calvinists are in error or not (obviously, you and I will disagree on that!), let me ask you this.
According to your theological understanding, are Calvinists, by virtue of their Calvinistic soteriology, unsaved?
Once again, according to your theological understanding, are "Arminians," (for lack of a more precise term), by virtue of their soteriology, saved?
No, the confusion for the Calvinists comes in trying to understand how they were saved.
Thus, in order to get assurance that they will remain saved they run to the Decrees.
Arminians have the opposite problem, they get saved correctly (at least the classical Arminians did) but then get concerned at keeping their salvation and begin doubting if they were ever really saved.
God in His mercy has made the New Testament Gospel very simple.