Finding something that "indicated" something is very different than "We went digging in Europa and found these alive creatures that look like Dolphins under the surface that live on Ammonia"

Society hasn't processed something we have no evidence of (yet), that doesn't make much sense. Ask "society" at large if they believe there are other species out there and most of them will say "I don't know" or "Probably not". In many places, religion is likely to be more believable to people than multi-cell life somewhere else than Earth.