In the Dec. 15 episode titled Earthlings Welcome Here, Sarah opens with this portentous monologue:
Enslaved, de Vaca chose to embrace his captors' beliefs and learn their ways. He became a healer. Over time, he was freed. And de Vaca attracted his own following. He believed he had the power over life and death. The desert had transformed him.
He was not the first. And he would not be the last.
I'm betting it was an unintentional mistake, not an intentional clue. No doubt the writers knew when Columbus sailed the ocean blue but didn't make the connection. At that moment, it meant "a long time ago" to them, not "two years before Columbus."
The narration includes a few other mistakes.
The unnamed captors were Indians, of course. Given that Cabeza de Vaca adopted their beliefs, it would've been nice to give them credit.
The Indians did not capture the men of the Narváez expedition immediately. Actually, Cabeza de Vaca was shipwrecked on the coast of Texas some six months later with eighty men. That was the beginning of his eight-year trek through the Southwest, which left him with only three companions.
Calling the Indians' actions "murder" is unfair. Soon after the Europeans arrived, Wikipedia tells what happened:
Finally, the explorer's full name was Álvar Núñez Cabeza de Vaca. His full last name was Cabeza de Vaca. Sarah was wrong to call him "de Vaca" ("of a cow"), a fragment of a name.
Overall, this bit is another case of two steps forward, one step back. The first step was mentioning Indians in the first place. Kudos to Terminator's writers for including another Native-themed reference.
The second step forward was crediting the Indians for having values superior to the Europeans'. The step back was implying the Indians were slavers and murderers--i.e., savages--without providing any context. Oh, well...can't win 'em all.
P.S. I sense a trend forming: a groundswell of support for Cabeza de Vaca in the media. Has his time finally arrived?
For more on the subject, see TV Shows Featuring Indians.