Earlier quoted context omitted.
Even just knowing they are there/coming or might arrive in 1000y would have huge effects on human society. Not being alone as a species has fundamental existential meaning and religion. Would the effects be good? The truth can have bad effects, but so does not confronting reality.
Would it really though? I would still have to attend that early meeting tomorrow. Still have to go grocery shopping. Still have to pay my mortgage. Finding signals from aliens on some distant planet would be interesting for one news cycle. Then everything would continue on as before.
Plus, more fundamentally, I think most people intuitively find knowledge itself valuable. Even if bringing much joy to many people doesn’t erase mortgages, this dismissive attitude seems unjustified. Imo