But you don’t know that to be the case, so shouldn’t we assume it’s possible? It’s not the possibility of communication with gravity waves that people are disp

But you don’t know that to be the case, so shouldn’t we assume it’s possible? It’s not the possibility of communication with gravity waves that people are disputing, it’s that without as much science fiction as FTL the energy requirements are so massive that you completely negate the arguments against light for the same purpose. Without this SF leap, you could just pour the energy into making a light as bright as e.g. a supernova and it would be multiple orders of magnitude cheaper and less difficult to generate the energy. This is completely ignoring the case where you know the direction you want to communicate with and build a laser. Yes, you can come up with plausible sounding SF ideas about why you might want to do this but please don’t pretend that it’s grounded in anything tangible.