I'm not talking about economics at all. The poster above me is talking about "freedom" in the same sense the FSF does--the freedom of the users of a program to (1) run it as they wish, for any purpose, (2) to study how it works, and change it to work as they wish, (3) to redistribute it as they wish, and (4) to redistribute any modified versions they make.
The reason they use GPL for their license, instead of something much simpler such as a BSD style license or MIT style license, is that they want to ensure that anyone who obtains their software will be able to do all of the things listed above.
As the poster above me put it:
For software, however, I like to use GPLv3 specifically
to prevent my labour from being used in a way that limits
the freedoms of others.
If I were to take a copy of his software, modify it, build a binary from the modified copy, and use that in my proprietary product without making the modified source available to the users of my product, he would believe that I have limited the freedom of the users of my product. If I were to use a code signing scheme in the firmware of my product to block software updates that are not signed by me, he would consider that as limiting the freedom of my users. If I make my users sign a legally binding agreement to not reverse engineer the code before I allow them to buy the product, he would consider that as limiting the freedom of my users.
He doesn't want me to be able to do any of that that, and so he uses GPLv3, which is only effective because of copyright. If copyright were eliminated, "Free Software" of the kind the FSF strives for is not possible.