While it is interesting to read this, there are a lot of confounding variables. Chances are countries which would allow zero ratings in the first place would also be more tolerant of other incarnations of excessive market power.
Note, that in spite of my opposition to net neutrality, I strongly support using traditional antitrust mechanisms to prevent firms' excessive market power and last mile monopolies from leading to unfair prices.
I had the same thought. The first paragraph concludes: And the evidence is in that it conclusively makes broadband more expensive, but this seems a bit much given the confounding variables you mention.
Note, that in spite of my opposition to net neutrality, I strongly support using traditional antitrust mechanisms to prevent firms' excessive market power and last mile monopolies from leading to unfair prices.