The author raises an interesting question in his notes - human nations & races have for much of human history distrusted each other & gone to war. And yet we broadcast our location and welcome out into the cosmos assuming that alien species will be benign and friendly!
IMO that fact is actually a pretty strong reason to doubt the dark forest hypothesis as a serious explanation for the lack of observable aliens. If we've broadcast ourselves to each other for thousands of years and now even to the universe, why should we expect that every single other civilization out there is consistently doing the exact opposite?
Arguably we've only been broadcasting outwards for something like 50 years, so the message hasn't gotten that far yet.
There was a plot element in the book about using a technique to broadcast a message more strongly than terrestrial antennas alone.
A spoiler alert
another plot element in the book was that it wasn't just the one way broadcast, but a response & counter-response that allowed distant aliens to determine distance and direction.
I thoroughly enjoyed Cixin Liu's Three Body series. Even if wildly unlikely I find the idea kind of comforting to existential dread despite it being possibly the worst fate for humanity.
If there was an advanced civ that fears competition, waiting for a random radio signal and then venturing on a crusade would not be the smart strategy.
You could instead launch relativistic kill missiles (pieces of rock) at all the planets in the galaxy before other civs emerge.
honestly i find the chain of suspicion to be the most problematic axiom for Dark Forest Theory. for example the turn of events with Bronze Age and Quantum, and eventually Gravity to be very unlikely, if enjoyable storytelling.
