And again, the outcome that the territory was conquered is the point.
It sucks to lose. Ask the folks in Saigon, 1975. Ask the Poles for a few centuries in Europe. Ask the French versus the Germans for three straight wars.
"It was pretty awful?"
Eh, yes and it was pretty awful for Serbs in western Yugoslavia in 1942 when the Ustazi decided to round exterminate them. Pretty awful to be in Cambodia when the Khmer Rouge decided to do its thing. It sucks to be on the losing end. Hell, ask any Egyptian from 1948 to 1973.
My objection is your using the term genocide carelessly as regards the application of manifest destiny. Particularly as you are not some rube from off the streets, you are far more eloquent than that.
Genocide is a specific approach, in terms of policy and intent, that is not synonymous with the general form of conquest.
Of course, both the Spaniards and the less Papist conquerors further north had the assistance of a few microbes here and there. I, for one, do not accept the various revisionist theories that there was a systematic program of biological warfare. I do accept the explanation in "Guns, Germs, and Steel" as a bit more plausible: a by product of interaction.
Genocide is a particular thing.