Again, the all-out Arab wars as part of this picture seem to elude you. Try this on for size as an expansion of your analogy:

Let's say we decide that we want Mexico, which is just sitting there, to be the fifty-first state, and we decide that the best way to do that is to get out the tanks and planes and shove all the Mexicans into Central America, or the ocean, whichever works.

We attack Mexico without warning.

Now let's say we get our asses kicked, and the Mexican army rolls up to the Oklahoma border. Texas is in Mexican hands. Mexicans start building villages in the Texas badlands (okay, Texas is already full of Mexicans, but work with me here.) Hey, they say. Years ago we were here first anyway, right? This used to be Spanish territory anyway, right?

Now certainly, from your viewpoint, or pretty much anyone's, the Texans can't honestly be blamed for getting violent about getting their "turf" back, although I'd like to think your average Texan might think more in terms of blowing up Mexican tanks and soldiers in Texas territory rather than sneaking into Mexico City and blowing up little Mexican kids.

However, the fact that these mythical Americans started the racist war with Mexico that got their state tossed back to the Hispanics can't be entirely overlooked either. While it doesn't settle the issue once and for all in anyone's favor, at least this analogy is a bit closer to the truth.