What conclusion are you referring to?
Comments made to the school's PR department are not conclusions.
In the article, the dinosaur issue is addressed only as a speculation. The following is the extent of their conclusion:
Formation of hierarchical branches is the principal feature of feathers17, and is therefore one of the chief issues in the origin and evolution of feathers. On the basis of some fossil evidence it has been proposed that a filamentous integument structure with a major central shaft and notched edges may be the prototype of feathers8-10. According to this model, the rachis would have formed first in evolution, then barbs, and finally barbules. Therefore, the rachis and barbs would be different entities and not interchangable (Fig. 5c). Alternatively, because barbs form first during development, it was proposed that barbs appeared first in integument evolution, and the rachis, a specialized form of fused barbs, appeared later as an evolutionary novelty16, 18. The fact that the barbs and the rachis can be converted experimentally in the laboratory favours the barb to rachis model. Our data suggest that a radially symmetric feather is more primitive than the bilaterally symmetric feather in terms of molecular and developmental mechanisms, and may have been the prototype of feathers (Fig. 5c). Some fossilized primitive skin appendages on Sinornithosaurus also favour this model11. Further modulation of BMP and Shh pathways may have led to the many varieties of feather seen today by regulating the number, shape and size of the rachis, barbs, and barbules1, 17, 30. This work provides evidence for the molecular mechanisms possibly involved in the evolution of feather branching.
Bolded part is their most definitive statement and it only addressed a possible (ie speculative) relation between their molecular findings and a specific evolutionary question involving feather branching.
The study is an excellent analysis of three known developmental modulatory factors (sonic, BMP and noggin)and their roles in feather re-growth after being plucked.
That's all.
Ideas and speculation are fine and that is why they are included in the final paragraph of the discussion.
Of course, but I think it represents the beginnings of an inference being formed. Despite the qualifications and hedging by the speaker, it seems clear that he at least considers the evolutionary aspect of it to be plausible.
Bolded part is their most definitive statement and it only addressed a possible (ie speculative) relation between their molecular findings and a specific evolutionary question involving feather branching.
True. But you know well, I am sure, that most conclusions are, to some extent, speculative. This is definitive proof of nothing, but it certainly illustrates a possible pathway for the evolution of feathers. Was this precisely how it happened? Of course we'll never know that for sure, but it is at least plausible...