It's about how software is licensed--the terms and conditions under which someone can make a copy. That's why it's called the GNU Public License, or the MIT License, and why there's a LICENSE file.
The mere act of copying does not convey ownership, and never has.
Free software licensing is an attempt to make copyright irrelevant: it's basically a no-copyright world it aims for, but then structured into the copyright world of licensing to use and distribute. It is nothing but a workaround, and copyleft uses it to make the default an even stronger case for reuse (by including sources).
In no-copyright world, you get a copy of something and do with it as you please. No licenses, no permissions. People frequently consider this "ownership" akin to owning a physical item (you get a copy of a book, or a toaster, and you do not ask for a license to tear a page out or repaint the toaster).
The creators of the GPL never said this. That's an interpretation that Richard Stallman would probably disagree with if you asked him.
> In no-copyright world, you get a copy of something and do with it as you please. No licenses, no permissions. People frequently consider this "ownership" akin to owning a physical item (you get a copy of a book, or a toaster, and you do not ask for a license to tear a page out or repaint the toaster).
I'm aware of all this. It's also irrelevant, because we live in a world with copyright, and despite the fever dreams of some, that's not changing any time soon.
Perhaps you should allow the person I was responding to answer for him/herself.
What the RMS's opinion on copyright in software was when he kicked off "free software" is pretty obvious from https://www.gnu.org/philosophy/why-free.en.html — you may certainly have a different interpretation of "you should be able to give a copy to your friend" than I do.
OSS licenses are fully part of the copyright system and could not exist without it. Maybe you are thinking of "public domain".
I do understand the copy left rationale - to ensure the freedom to modify and for the community to benefit from those modifications, it is necessary to use the machinery of control!