Dear Axel,
You are right in one thing: you try to think by yourself on all these questions to make your very *own* opinion and not just stick to a fundamental text that would be just like a holy bible for the free software supporters.
But I really think you missed two points in your thinking.
1. What is ownership and what is authorship ===========================================
The first is what is ownership on software, and the fact that it is really different from the authorship. Copyright is what in law is the closest to the notion of ownership of software, although it is limited in time. So the one who is the closest to be the "owner" of a piece of software is the copyright holder.
As for something you own, you can sell and buy copyright ("ownership"). But you cannot buy or sell authorship (hiring a writer to write a book and putting your name on it is punished by law, at least where I live, in France). The author is just the *original* copyright holder ("owner") of the work.
Suppose you are hired to write (proprietary) software for a company. In fact you will be hired not only to write it, but also to cease your copyright ("ownership"). You won't be the copyright holder anymore, but you will still be the author (you are still the that wrote the software, whoever is "owner" is).
So authorship and "ownership" are two very different things as you can, at the same time, have one and not the other.
2. What is freedom and what is power ====================================
The second point I think you really missed is what is a freedom and what is a power.
It seems you started your thinking by reading "Why Software Should Not Have Owners" (http://www.gnu.org/philosophy/why-free.html). You should go on reading "Freedom or Power?" (http://www.gnu.org/philosophy/freedom-or-power.html).
Short quoting:
"Freedom is being able to make decisions that affect mainly you. Power is being able to make decisions that affect others more than you."
Before we continue, let's have a look on how far the notion of ownership can apply to immaterial things, like information, and software which is a kind of information (can you agree with this?). The prerogative of the copyright holder ("owner") is to edict at which conditions the software can be used/copied/modified. He can even decide to prevent anyone from using/copying/modifying it (and that is unfortunately a common practice).
Claiming the freedom to do so is in fact claiming a power. You are just claiming a *power* to prevent others to do what they want, what their *freedom* should grant them, even with "your" software, or more accurately the software you are the *author* of.
So there are no two kinds of freedom that oppose, the one of the copyright holder and the one of the users. There is a quest for freedom of the users against the manifestation of a power of the copyright holder.
This power granted by law at this time, which some of us feel is wrong. And in this point of view, the GPL (and beside it, the notion of copyleft) is just a workaround for this. You can see it as a temporary and realist solution to the problem.
The true and final solution would be that law stop granting such a power to copyright holders => software don't have owners.
-- Guillaume Ponce http://www.guillaumeponce.org/