Right but then that relies on not existing in a dark forest. That is, you can detect signs of alien life, but then those signs tell you horrible things.

The situation we have is that we see nothing.

I guess the answer is that some civilisations reach a point where they broadcast themselves and get destroyed, whilst other civilisations reach a point where they receive those broadcasts and don’t reply before hearing the other civilisation get destroyed. So somehow they were listening at the exact right moment to discover that others are getting killed without responding, and that happened enough times that there is a whole universe full of quiet civilisations.

I still don’t see the A to B. I cannot imagine any species curious enough to detect alien life and insular enough to not respond. If we got those signs we would reply immediately, almost definitely.