Interesting. I had forgotten all about that quote.
If Kino were found there as a baby, that would reconcile his speech with his futuristic heritage. Still, I don't see the point in Kino being from the future - it really adds nothing to the story. You would think that if he was foreign in origin, the writers would have made something of it, wouldn't you?
Maybe they had something planned, but didn't actually do it. But they left this speech for flavor or something. It could do the plot no harm. Also, Kino being from the future would mean that he is not the first person in Guardia line by far. So, maybe what happened was this: The Guardia line was actually, just common people who lived normally in the world... one of those prehistoric cavemen, going all the way until Kino time travels to prehistory, thus being found and raised and then becoming the right-hand for Ayla, and eventually married her, making the Guardia line finally gain a hold on power.