I think the problem is, races which can travel through space very quickly probably don't have much interest in those that don't, almost like how we see wildlife, maybe they would investigate us like we do our surroundings, but can't have a good relationship. Then you have races which can't travel through space, and they can't talk to anyone even if they want to, the only way they could do it is if the more advanced races set them up some kind of messaging system. However the more advanced races can keep themselves out of a lot of unessesary bother if they just stay out of it, so thats probably what they do. Pretty sure its what I would do

Its quite funny to think aswell, when humans declare territory, the wildlife kind of falls under it without any say in the matter. So if we are in a territory, then we kind of have a political situation going on which we don't even know about. Its possible we are protected from interference or attack, ie if you attack the planet you get thrown in "jail" or whatever the equivalent is ;D But I mean, the point is, if there are lots of aliens around, it must be a well organised system, there would have to be lead races which keep things in order. I can't believe things would just naturally work out and everyone is friendly with each other, maybe with the really high races but not the lower ones.
But also how far does the term "alien" go, and when do they start becoming "gods"? You could even see the whole universe as a creation from an alien race which just builds universes, always coming up with some different way to sustain life. Its quite interesting because the first universes could start out being really simple, and from them they'd learn from each universe they make, how to improve the next ones, which would mean we're in a sort of string of evolutions of universes.
But you have to wonder, what a universe is. Is it like a huge galaxy of galaxies, or is it a collection of them, or is it like a never ending 3 dimensional grid of universes which gradually change as you travel from one to the next, so if you travelled 1000 universes you would end up somewhere really weird? It would be boring if the whole universe was stars and planets everywhere eh ;D And everything made out of atoms, get real, lol.
But anyway I suppose its kind of like the afterlife, you don't know if it exists until you see it for yourself. Not that I can say I've seen either. But if you say they don't exist, theres nothing to say about it, but as soon as you consider that they might exist, theres all sorts of possibilities. But not many facts at the moment unfortunately ;P