Never underestimate the bandwidth of a truckload of hard disks.
Latency hardly matters when the majority of the lag is the 100 light year leg: you first spread out your whole message to the surface of the filter with a high bandwidth distribution medium. Then each section of the filter switches in sync, encoding the message without relying on a real-time input from a central location light seconds away
what you are saying could also be: other civilizations would do the same as we do. send small unmanned drones into space, and not just signals. they are much slower, but allow much more information and better reaction time, if the onboard logic does that. and they are not mistaken for something else, as in this case.
Latency hardly matters when the majority of the lag is the 100 light year leg: you first spread out your whole message to the surface of the filter with a high bandwidth distribution medium. Then each section of the filter switches in sync, encoding the message without relying on a real-time input from a central location light seconds away