This isn't accurate. There are certain axioms in the world- self evident truths that ultimately lead to a foundation of basic, inalienable rights that every human can demand. For example, the right to life and the right to property are paramount.
Humans don't have rights, Silly
😛 We're random collocations of atoms. Rights are a human construct, ultimately an ethical concept. Talking about "rights" just roots human morality in spirituality and irrationality, which doesn't help anything.
The right to free speech is actually a mere corollary. So long as the right to property exists, free speech will never completely die. One can always speak their mind on private property, such as in their home, or potentially on someone else's private property if both parties agree.
Remember Nazi Germany? The Germans had a right to property, but their own children spied upon them. Do not say that the right to property did not exist in Nazi Germany, because it did for almost everyone not convicted of a crime against Germany -- even in a Lbertarian paradise, people are deprived of their property for crimes...
By the same token, if you take away the right to own a printing press, it doesn't really matter if you still have the right to free speech.
So because I do not own a university, it does not matter if I have the right to be educated at one? Because I cannot own a national forest, I cannot walk through it? Because most of the nomadic Native Americans did not lay claim to the lands on which they traveled, they could not hunt and fish on it?
The right to operate a business and mutually agree to engage in transactions with your customers without external interference is also a right that can be proven- it is not an opinion.
Then prove it. You can prove that it might be desirable, but you cannot prove that it is a right -- again, rights do not exist outside of the human mind. Do you think rabbits lecture hawks on their respective rights and responsibilities?
If you don't accept the right to life or property, you must absolutely not accept it. For example, you have to openly accept the fact that I can enter your home and take what I like. Similarly, if you don't absolutely accept the right to life, you accept that your life can be subordinated to me- in other words, I can take you as my slave.
Again, the right does not exist -- so deliberating imaginary laws for acceptance of an imaginary right gets us nowhere. I could similarly say that I have a right to sexual congress with anyone I meet, but if I pass up having sex with one quadroplegic midget, it means anyone in the world could rape me at will.
How about this: the world has never been legally bought or sold, since it was never legally owned, since control over the resources for existence is a non-negotiable good (impinges on rights to life). Therefore, the world is the property of all, people who damage the world are guilty of crimes against the property of the human race, and therefore should rectify the damage they have inflicted much like a kid would clean up their spilled milk. All production is derived from natural resources, either directly or indirectly, and thus needs a lowered sale price in proportion to the effects of its creation upon the environment in the form of positive environmental action in order to compensate the world for that "withdrawal."
You can "prove" anything, but you can't prove anything, and rights simply do not exist except as human constructs. I'm not saying that rights are a bad thing -- I'm an anarchist, and against coercion -- but we have to approach this on a sane, philosophical playing field.
Unfortunately, you are not alone in your quest for non-absolutism. You are joined by many others, including most politicians.
When I think of absolutist politicians... well, I think you know a few of the names that come to mind.