Thus, the new-found evidence discussed in the article serves only to dramatize something these scientists want because of their philosophical predispositions,

Thus, the new-found evidence discussed in the article serves only to dramatize something these scientists want because of their philosophical predispositions, I don't think this is entirely true here. You've loaded the question by making an assumption, "It is morally repugnant to mistreat animals regardless of the intelligence of the animal" which not everyone will agree with. In fact, I suspect the vast majority of people do not: every day millions of people knowingly eat meat produced from animals that were horrifically mistreated, despite the fact that they could have eaten something else, often for a lower price. Why? Because it tastes good, and a lot of people don't care about the suffering of cows. Suppose the following moral axiom that some hypothetical person might hold: "Mistreating any sapient being is equivalently morally wrong as mistreating a human." Therefore, if scientists can prove that an animal is sapient, those who follow such a belief will agree that such an animal should not be mistreated. I don't see the problem with scientists arguing that an animal is sapient.