We are researchers, we try to explain the universe by improving our understanding of the physical processes that lie behind what we observe. The moment we bring aliens or gods into the picture to explain something for which we don't have an answer, we are doing a disservice to science.
Although the possibility that FRBs are produced by
extragalactic civilizations is more speculative than
an astrophysical origin, quantifying the requirements
necessary for an artificial origin serves, at the very
least, the important purpose of enabling astronomers to
rule it out with future data.
It should be possible to distinguish between FRBs of
natural and artificial (light sail) origin based on the
expected shape of the pulse, as the beam sweeps by to
power the light sail. More specifically, the sail
would cast a moving shadow on the observed beam,
thereby leading to a diffraction pattern and multiple
peaks in the light curve based on the sail geometry.
A series of short symmetric bursts would be observed as
the beam’s path intersects with the observer’s line of
sight. Hence, looking for similar signatures in the
signal could help determine whether FRBs are powered by
extragalactic civilizations...If the elvish hypothesis proposes some experiments for testing and disproving it, then yes - it sounds more scientific.
We don't even know for sure that the majority of FRB data we have are from non-terrestrial phenomena. FRB occurrences at Parkes correlate strongly with lightning storms near the observatory.
But sure, it's probably angels or little green men. Why not. That's a hypothesis, you're doing science Jimmy!
With this attitude, much archeological evidence of pre-Columbian civilizations would never have been found. In fact, the entire field of archaeology wouldn't exist.
Your attitude turns people off science; it's a plodding, unimaginative attitude that pours cold water on every novel idea without even bothering to explore it properly. The history of science is full of discoveries resulting from accident or whimsy, and I think speculation is an important exercise. Nobody ever got to the top of a mountain by meticulously documenting every step of the route.
So there's a risk you'll pin some hopes on an idea that turns out to be wrong. That shouldn't be bad for your career unless you do it all the time. A scientist who is never wrong about anything isn't taking any risks.
If you want that kind of excitement, try other area, in here, the only excitement comes from finding an answer to a problem based on science, not in some sci-fi novel.
P.S.: The simple explanation in this case is of course some physical process we can't understand. Not an alien civilization making planet sized machines to power their spaceships. This ain't star wars.