I think it makes sense in the "beer is tangible" and "speech is not" sense (to my brain anyway). If I saw a "free beer" sign in a window I'd probably be inclined to think (albeit suspiciously) that there might be a frosty mug inside at no cost to me. Whereas if I saw a "free speech" sign, I'd assume they support my right to say whatever I want (or I suppose maybe that there's a lecture going on inside with no admittance fee).
We all got different brains though, shoutout learning from others perspectives, ty for sharing yours.