That's one of my problems with his argument. The author seems to think he has a fundamental right to access the produce of media companies... but only on terms he finds reasonable, of course.
As you say, rights are often malleable - and reevaluating and redefining them (from both sides of this debate) should be an ongoing process.
The way I see it is that the author is using this blog post to fight for what he believes are his rights, and the businesses are fighting for what they believe are their rights. Philosophical/Moral arguments aside, this war will be won by whoever is louder/more influential.
As you say, rights are often malleable - and reevaluating and redefining them (from both sides of this debate) should be an ongoing process.