IMO ants are a much better analogy to aliens than "some human tribe". They're human, we can communicate with them. That's not very alien.
The analogy doesn't stand because ants are not sapient creatures. They are not capable of communication in any way that would allow for any kind of diplomatic negotiations to take place over territory rights. We, however, are sapient creatures and can be communicated with. We would be a comparatively primitive society interacting with a more advanced one, and the only meaningful comparison we can draw from that would be more advanced humans interacting with primitive humans.
But even if we go with your ants analogy, my point still stands. Would you advocate taking military action against all ant-kind if one of your family members was swarmed and killed by a colony of ants after accidentally stepping on their anthill? No, because, again, that would be an unreasonable response.
Why is it us that own the planet and not insects, considering they outnumber us by the billions and have infested every crack and crevice of this planet?
Because we are the dominant species on this planet. I think it's perfectly fair and reasonable to consider the dominant species on any planet to be the owner of that planet. Insects may outnumber us, but numbers alone do not make a particular species dominant.
Your attitude is so American it hurts.
You say this like its a bad thing.
Would you also shoot down a bald eagle if it flew over your house?
No, because I don't see a bald eagle as a threat. I know he's just a creature living his life and won't take any aggressive action against me unless I provoke it. Some weird alien from another planet though? Not so much. I have no idea why they are here,and until they communicate their intentions, I will assume they have hostile intent.
Do we own the moon because we've stepped foot on it?
In the absence of any other legitimate claim to it? Sure. And since I don't see any alien settlements on it and I do see the flag of a human nation planted on it, I'd say that makes the moon ours.
You just cannot step outside of the human bubble and see our actions for what they really are: Laying down a philosophical groundwork to justify all of our actions.
Oh I can, I'm just a very "humanity first" kind of person. I do believe we, as a species, have an inherent right to claim ownership over anything and everything we lay our eyes on. If some alien species out there doesn't like that attitude, they are welcome to try to stop us.
That's not to say I think other lifeforms have no rights or claims to anything, just that they can only exercise those rights when they don't negatively impact or inconvenience humanity in any way.
To make my position more clear: I was the person rooting for the humans in Avatar. And no, I'm not trolling or joking. The humans may have seemed like the jerks, but consider they were fighting to ensure humanity's survival. Earth was a dying world and our civilization was on the brink of collapse. In that scenario, is it really so shocking that the so-called antagonists were putting humanity's interests above the interests of some tree-dwelling primitive aliens?