This becomes much less clear if you bother to consider things like how that software came to exist in the first place.
Consider that there are things you can do, things you can't (or aren't permitted to) do, and things outside of possibility (eg web browsing before the internet was invented).
Requiring software to be Free/unrestricted reduces "things you can't do", which given a fixed set of possibilities increases "things you can do".
But the set of possibilities is not fixed. Depending on how any particular software being free affects the rate that things are removed from "outside of possibility", it could either increase or decrease the amount of "things you can do".
Edit: Is your freedom defined by how much you can do, by how much you can't do, or by the ratio of how much you can vs can't do? It's silly to be concerned only with the second of those.