My mistake.
When I read the part:
I wonder how the Tejanos in Tejas feel about all those obnoxious white invaders who are trying to make the natives unlearn their own language.
I thought you were saying that the white people of Texas were wrong.
I concluded that you would advocate us (white folks) righting a wrong.
Well, I am more or less saying that the white people of Texas are wrong, and am advocating righting that wrong, but I never mentioned giving Texas back to the natives. This discussion is about languages and the mandating the use thereof, not redrawing political borders.
For a really long time before we got here the people of Mexico moved with unrestricted impunity into and out of what we now call Texas (kind of like the people of Ohio and Michigan move back and forth between those two states currently). They spoke their native languages while doing it, too. Then, suddenly, Texas was awash in foreigners, immigrants and settlers who spoke a different language, few of which felt compelled to learn the local language, especially as their numbers swelled. The natives kept their own language, as well.
Then, suddenly, Texas was its own country, but the languages remained, as it's hard to snap a finger and make people learn a new culture and a new language.
Then, just as suddenly, Texas was annexed as part of the United States, was promoted to a State. The people were the same, tho.
Now, the good white folks of Texas, immigrants and descendants of immigrants one and all (or, depending on your perspective - invaders), want to require the natives to cast away their historical culture and languages in favor of one imposed upon them by the white folks. The white folks literally want to deprive the natives of being who they are, of the liberty to be themselves.
The natives, human nature being what it is, are resiting having others tell them what to do and how to live, and are naturally resisting having to learn a new language "just because I said so". Put the shoe on the other foot, and the white folks would resist (and are resisting) learning a new language while still living in their native land, too. It's a battle wills and a battle of liberty. And the white folks are, mostly, wrong.
Texas should not and will not be "given back" to Mexico. It is what it is. But you've still got to allow people the liberty to be themselves. If you think it' OK to tell people they must use a different language, then go down south and tell people they aren't allowed to say "fixin' to" (or in Mississippi, "fidn' da"), or go to an Amish community and tell them they can't speak German, or go to most anywhere in Ohio and tell them they can't use "worsch" when describing the cleaning of dishes, vehicles or laundry.