Everyone jumps to the most wonderous conclusion possible when it comes alien life, but this in my opinion is the most plausible likelihood. Humanity is not only a relatively new civilization, but it would also kind of make sense that in the grand scheme of things we aren't really all that important as a species. We only just reached our own moon less than 100 years ago. I think the idea of humanity being just a mediocre species in the grand scheme of things is scarier thought to some people over the idea that we are of some unique importance.
It would also make sense given that lots of "official" declassified reports of UAP/UFOs tend to focus around nuclear and military testing sites as well as active war zones. Kind of like they are checking to make sure we aren't annihilating ourselves. I can just imagine an alien civilization laughing over the fact those stupid hairless apes got into another war and being informed in sheer horror that not only did we split the atom, we used it as a weapon against our own kind just to see what would happen instead of using it as an energy source.