So … could it be that we’re looking at Klingon Cape Canaverals? That we are occasionally catching the flash of the mother-of-all-lasers as they boost alien craft to speeds that would allow them to travel from star to star quickly enough that the passengers who boarded would still be alive to get off at the other end? Yes, that’s possible. But on the other hand, it’s just about always possible (and inevitably tempting) to ascribe puzzling astronomical discoveries to the work of advanced beings. It was much more exciting to think that pulsars might be messaging apparatus used by extraterrestrials, or that flickering quasars were just another effort by cosmic company to get in touch. But in the end, it turns out that Nature is both ingenious and full of surprises, so I’d keep the “alien explanation” for FRBs at the bottom of the drawer for now.
In addition, the repeated nature of at least one of these FRBs would require a fairly specific (and therefore, suspect) geometry as well as a busy schedule on the part of the supposed alien launch team.
Never say never, of course, and this is an appealing idea. But my first reaction is to bet on the workings of Nature, rather than that of aliens with a hankering to roam.