It’s not as complex as you’re choosing to make it. When someone tells you, “There’s free beer at Oktoberfest,” is your first thought that the beer has no monetary cost, or that the beer is unencumbered by particular legal restrictions?

Now someone tells you, “There’s free speech at Oktoberfest.” Is your first thought that there’s no monetary cost to expression, or that the expression is unencumbered by particular legal restrictions?

(Happily, Oktoberfest has both.)

Think of them as the _slightly_ longer "Free as in 'free beer' " and "Free as in 'free speech' ". When beer is described as “free,” it’s understood to be gratis. When speech is described as free, it’s understood to be libre. These are used as examples for more ambiguous situations, since software can be one, the other, both, or neither.