> we're finding evidence of absence everywhere we look.

Show your work. Show me any such "evidence".

You seem to be unfamiliar even with what kind of data cosmologists and astronomers process.

We've been to the moon. There are no machines. We've been to Mars (via machines). There are no civilizations. We've seen the orbits of thousands of planets which are absolutely too hot for any biological processes to synthesize. We've scanned countless stars and determined them to be too unstable for anything to survive in their orbit. We've looked into every single confusing thing in the universe we could find and have seen natural explanations for nearly every single phenomenon.

Do you think we just don't know anything about the universe? There is tons of evidence of absence. It might not be complete enough to make a guess yet, and that's a fine argument to make, but it's weird to pretend that the evidence doesn't exist.

edit: And again, while it's not evidence of absence, I'm still waiting for a galactic signpost to pop up somewhere. Unless you've got some explanation for why not one single civilization anywhere, even ones which have left their home planet and have nothing too serious to worry about with respect to retaliation?