My ideas of cosmology, and evolution, and all that are often anthropic. Just consider how our evolution was dependent on the pre-existing nature of the universe, and how that causal connection might be scrutinized....

If life cannot fully develop unless it is free from interference from other alien intelligences, then our existence suggests that interstellar travel is impossible. Extrapolating from that pre-condition for our dominance on our own planet, what is the purpose of having a universe teeming with trillions of civilizations (or uncivilizations), each dominant on their own worlds, if none of them can ever interact? It doesn't make sense.

I suppose there is always the fallback argument that life in the universe is a random accident and that there is no purpose to it. Life simply might not have occurred under different conditions, and we have to accept the limitations that come with the conditions that allowed us to exist in the first place. Maybe we ought to choose a different challenge if space seems too vast a hurdle. However, while I accept, say, FTL travel, as one of the things that aren't allowed in this universe (as we understand it), I'm not sure if I accept that interstellar travel of any kind is utterly and completely disallowed.

Not knowing... is one of the things about life that sucks.