On Junco's point of why we haven't communicated with them: how are we supposed to make contact with them? There are thousands of different languages just on this planet; a lot of them come from the same root languages, but we can't communicate effectively with one another. The languages developed across the galaxy would likely be completely foreign.
(All the communication stuff is assuming we don't just blow the things out of the sky.
)
True, but bare in mind that although their way of thinking and operating could completely alien to our own ways, there is going to be stuff like mathematics, physics and chemistry that we understand, and that they will have to understand too. If they're exploring space, then that might mean they have some sense of sentiment and curiousity. I mean why else would you? It could be that these traits are actually required for intelligent life. So you might reasonably assume they would like to communicate and learn like we do.
https://en.wikipedia.org/wiki/Contents_ ... den_Record
The contents of the voyager craft is a very imaginative effort to record what it means to be a human being, and we produced that in the 1970's less than 20 years after our first spacecraft, and we have since speculated massively on how we would communicate with aliens. These UFO's based on these sort of stories seem to be indifferent to whether they are detected or not. If they are extra terrestial and they've travelled this far and remain uncaptured, then they were probably engineered by super intelligent beings. Even a drone created by them would be so intelligent it would invent ways to communicate.
Maybe they are indifferent and we're of no consequence to them at all. So then, again, why are they here?