The author hesitated for a long time before publishing this article, because there are strong ethical issues. Documenting the effects of censorship can be seen as helping censors. For instance, if measurements show that censorship is very limited in practice, it may motivate some authorities to increase the pressure and its negative consequences. But I believe that censors are already better informed than the average citizen and that it is necessary to have factual information in order to have an informed debate in democracies.
Another big ethics issue concerns the measurements themselves. Is there a risk of endangering people who host a probe by doing DNS lookups for illegal/forbidden/questionable things (for instance DNS lookup for a porn site from a probe in Iran)? Today, the DNS is typically "under the radar" for most surveillance activities. Doing an HTTP request for an illegal site attracts attention to you in some countries (and it is one of the reasons why RIPE Atlas probes do not perform HTTP queries for arbitrary URLs), but it does not seem to be the case (yet) for DNS requests. (See RFC 7626, "DNS Privacy Considerations".)