At the heart of this article is the claim that buying equity is a form of theft. That is an extreme claim (in the sense of surprising, remarkable, unusual, and one that needs a lot more support than ordinary claims). It is inadequately defended here. The argument that it violates fair exchange is tautological.
The article is clearly written from a bit of a Marxian perspective and I think there's a lot assumed ... presuppositions about exploitation and value theory. So yeah, even though on first skim I think I agree with the thrust of this article, I think you're right it's poorly defended, assuming it's at all for an audience outside of people who already think this way.
One could probably say that the privatisation of human communication is a form of "initial accumulation", or maybe just another step toward appropriation of culture, but that's apparently not the angle that the author decided to explore (can't be sure, I couldn't do better than skim that text which looked wrong in too many ways).