That’s my take on it too. It could just be natural selection - noisy, young Civs get eaten by the big bad space predator, while inherently quieter Civs survive.

So the universe could be full of life but it’s the sort of life that doesn’t attract attention.

There doesn’t even have to be a “big bad” in this situation either, it could simply be that the sort of life that creates noisy Civs, is also the kind of life that ends up annihilating itself before it gets advanced enough to be able to make contact with others. That sort of crosses over into the Great Filter though.