Well, I can't say whether you're wrong, because people do use the term to describe different concepts. If we're using the concept of a libertarian free will - doing whatever you want - I don't think people possess this... We are subject to a lot of constraints. I think God would be the only being who would possibly qualify for having that sort of free will. As far as people go, our "free will" consists of being able to decide between different available options, but not all options are available to us. So I suppose from my perspective, the closest we could get to experiencing a libertarian free will would be to conform as closely as possible to God's will, since all options (free of any physical or other constraints) are available to Him.

So for me, an argument could be made that humanity's will was more free before the fall, and that sin (as in choosing to act in ways that don't conform to God's will) is responsible for constraints on our freedom. The most obvious constraints being physical ones such as death, sickness, pain, etc. which the Bible describes as being direct results of the fall.

I don't expect that you, as an atheist, would agree with the idea that a truly free will consists of choosing to conform fully to God's will, though.