And I'm practicing supporting the nascent Free Culture movement. The goal is to make a whole sector which is composed of freely given and freely received cultural services and objects. Despite the commodified state of the art world and music scene, a Free Culture was historically a goal of a significant segment of artists and musicians. Amanda Palmer is one example of someone who is striving toward a Free Culture--the decommodification of art and cultural services.
You're speaking of two different elements here: the right of an artist to make a living of his art (the commercializing of art) and the rights of the artist to retain control of his art. These are separate issues that have traditionally gone hand-in-hand, but need special addressing.
The first part is the obvious monetization of "culture" (art, music, literature, etc). While there is some merit to the notion that the public domain needs to expand (the so-called Disney clause that has extended the copyright of Mickey Mouse is long overdue for an overhaul) the idea that a creator should not profit from his art seems counter-intuitive. I can't paint, so I pay for the time and talent of someone who can to make me a painting to hang in my living room. Patronage has existed since medieval times, and I'm certain you don't believe anyone should just "give" away their art for free. Taylor Swift, Mike Mearls, Michelangelo, they all profited from their talent. To say they should give away their gift for free is a hard pill to swallow.
Moreso, giving something to the Public Domain means you no longer control its destiny. Anyone can create their own vision of your art and you have no contorl over it. Wizards has had a dickens of a time combating Pathfinder, a creation of the OGL with its stiff restrictions. Imagine what Paizo could have done if they could have lifted the name "D&D" to go along with it! Just because you can derive an idea from an older source (Superman is really a Herculean myth brought to modern times, doesn't mean I get to make Superman stories) doesn't mean the derivatives are open as well. A world where an creator cannot profit nor control his art is not a world of artists, its a world devoid of creative genius.
Now, if we lived in a world where all artists were given stipends from the people directly to sit and create stuff, I could see the tables turning. Alas, we don't. So its not fair to ask them to give away their fruits for free, esp without stipulation on its use.
Oh, and I'd be real careful mucking around with Tolkien's work: Chris will sue for derivatives that hew too close to his father's work faster than you can say "hobbit, ent, and balrog". Gygax learned that the hard way.