system
Given the following post, respond as if you're commenting on Reddit:
human
[Guardians of the Galaxy] *Spoilers* Why does the galaxy leave Earth alone.

**Movie Spoilers Continue on only if you're up to date in the Marvel Cinematic Univers**

At the end of the movie Nova Prime tells Star-Lord that he's only half terran meaning that the scientists would know enough about earth DNA to know what is and what isn't human. He also gets abducted as a child with no repercussions from the galactic community. Aliens also seem to have heard enough about earth enough to not be confused when he talks about Earth and being Terran.

There was also a somewhat recent intergalactic Chitauri invasion of earth that a good portion of the galaxy should have heard about that was led by an Asgardian and backed by Thanos (though it's unclear if others know of Thanos' involvement).

Basically, why is Earth so known by the galactic community but the galactic community is fairly unknown to Earth? Is there some sort of Marvel Prime Directive or something?
gpt
Let's be honest, prior to the current batch of superhumans that seem to be popping up on Earth, there wasn't much going on there to be concerned about.

Other spacefaring races would know about Earth because they've happened across it and it's part of the Asgardian's dimensional network, but there's no reason to stop there, it's populated with near-primitive monkeys for the most part.

The comes Loki, who promises Thanos something that plays into his future plans, in exchange for having the Chitauri invade the silly little rock for him. Nobody in the rest of the universe should care, because nobody knows what Thanos is really up to, and who gives a crap if the third dirt ball from a far flung yellow sun gets added to the Chitauri sandbox?

Conversely, Earth is so behind the scale technologically that aliens could pretty much come and go as they pleased and only a few agencies even had a chance to know. 

That was until the Chitauri arrived.

Now the world knows that we're not alone in the universe, they just don't know how crowded it can be out there.