"free as in speech, not beer":

"free speech", the right to say what you want without legal restrictions from the state

"free beer", beer you don't need to pay for

Nothing to do with beer making you "feel free" (?) or whatever

Then again, free speech is not about being able to modify speech, release your own version of another's speech, and so on (e.g. the US has "free speech" but MLK's dream speech is still copyrighted).

Perhaps a better slogan would be:

"Free as in free sex, not beer"

And if the slogan wasn't meant for corporations too, and wasn't coined in the puritan 80s/90s, it might have been...