On reflection, I think I see the legal angle here (which I did not in the prior thread). Activist groups have long looked for a hook by which to bring class actions against those whom they see as perpetrators of wrongs that they wish to stop. In this case, it is commercial tuna fishermen. However, the courts have denied them the right to sue on behalf of the dolphins (which are accidentally killed in the course of industrial tuna fishing) on grounds that dolphins aren't human beings and therefore do not have 'standing' to sue. This means that the activist groups also cannot bring class actions in the name of the dolphins. Of course, if the dolphins are 'self-aware,' then they arguably can be treated in a special way by the courts - as 'non-human humans' - and be given the right to sue. The research is being cast as disinterested science, but I believe it may be motivated by this extra-scientific goal and that is why it is routinely presented along with arguments for better ethical treatment of the dolphins. In essence, the bottom line will be this: better ethical treatment = enforceable legal rights (i.e., enforceable by activist groups suing tuna fisherman in federal court once a court recognizes their right to bring such suits on behalf of a 'self-aware' species that now should have 'standing' to sue).

As I have come to see this in such a light, I believe the science here may be authentic but it may equally be agenda-driven, potentially making its findings suspect. I leave that to those who understand the scientific issues (I do not) but it does need to be evaluated in light of this background motive and its implications.

(Its a question, not a rhetoric. eg. Killing humans is not OK, killing poultry is, intelligent aliens from space is not.)