> Depends on the context. We certainly knew nobody else had nukes.

You wouldn't be able to know this over the vast distances of the universe.

People are arguing two contradictory things: these are unfathomable alien civilizations with motivation and timescale we cannot comprehend, but we would perfectly understand their tech level, location, and capability of striking back.

It doesn't add up. It's a scifi premise needed for interesting plot conflict.