To borrow a term from our postmodernist friends, let's deconstruct that a bit. "We" clearly means Hispanics, or perhaps some narrower group like Mexicans. "You" refers to whites. The meaning of the argument is that the America is just a piece of land claimed by two racial groups--whites and Latinos--and Hispanics have dibs since they arrived first.
Set aside the question of who showed up first. In this scenario, there is no United States of America and no American citizens. There are two racial groups fighting over land. This is the worldview of a thoroughgoing racialist. How is the logic of the argument different from the white nationalist who argues that North America belongs to the white race because it was developed by them?
The outlook of a true American citizen is that only Americans can decide who can move here, and that decision should be based only on what is in the long-term interests of the nation. We Americans have all been here the same length of time--since the birth of the country. Arguments advancing the interests of one racial group against another are illegitimate to the citizen.
This "we got here first" argument betrays the mind of a tribalist: "I am a cell in a racial body that is in conflict with the racial body of which you are a cell. I operate on this understanding, and so do you, white guy. Your kind believes the same way and always has. Nationhood and citizenship have nothing to do with it. We're not on the same team."
Liberal delusions to the contrary, very few whites think like that. When whites criticize illegal immigration for its lawlessness and cost to the country, they mean just that. Of course, "illegal immigration hurts me" is a common underlying sentiment, but "it hurts my race" is rare indeed.
Whites, even savvy whites, let minorities pull this crap all the time. Activists start talking like brown Nazis, and whites think it's a perfectly legitimate argument.
Critics are right when they claim that whites think they are superior to others, but they're looking at the wrong attitudes. White superiority goes like this: Enlightened humans are not tribalists. Non-whites are naturally (and properly) tribalists. Therefore, non-whites are not enlightened humans like us. (The last step is usually not thought through, but it's the logical conclusion). White tribalists are especially low because, while such behavior is normal for people of color, it is beneath a white person.
I'm not a supremacist because I think non-whites are equal to me and therefore should be held to the standards I impose on myself (non-tribalism). They are not inferiors like children who cannot reach the lofty heights where I reside.
The only problem with my expectations of non-whites is that I look like Pollyanna in a pink dress.