I think we're the North Sentinelese of the Milky Way and we're being purposefully insulated so we develop technologically and sociologically up to a certain point where we'll be able to join everyone else. I doubt they'll say anything. That's the point. In fact i think we're being shielded as a kindness, possibly protected too. We, as a species, can't even leave the solar system and return. I'm guessing an advanced enough civilization could create a believable enough reproduction of the universe for us to study.
I think the difference between the alien UN and our global organization is probably the same level as the difference between our UN and the North Sentinel Island tribal elders.
It just doesn't make sense that the galaxy is empty. But my theory is just my best guess. I have no concrete evidence. I do think there are some mighty coincidences around here. For instance, a solar system stocked with several planets and minerals and a long life stable star, almost ideal from all the various star types available. A random meteorite hitting the earth after millions of years of dinosaurs not developing intelligent life. A very logical progression of bodies for a space faring civilization to grow. First the moon, then mars, then venus, etc. A lot of asteroids that seem to zip by Earth but always near miss at an alarming common rate. Jupiter strategically placed to keep Earth safe from a large number of meteors and other celestial bodies.
I think humans are a benevolent, non intrusive biological experiment by an advanced species or at the very least a protected species in some nature reserve. Them interacting with us could potentially hamper our development. It could be that religions were their previous attempts but didn't work out so well.