In any case, what constitutes "sneering" at their oral tradition? As you said, science & religion are not the same. So what should a scientist do if their beliefs differ from science's?

Sneering would be something like saying, and I mean this with all due respect, "you didn't come out of the ground in that canyon, we all came from Africa" - misconstruing what they're saying, seeking to correct rather than understand, generally being rude and dismissive. If someone shares something with you, it's up to you to figure out how and whether to incorporate it into your epistemology; if you're having trouble with that, it might be tempting to say, "the problem is that your epistemology sucks," but a.) That's an indecent way to treat someone and b.) No one is going to learn anything that way and c.) The problem is actually that you gave up on trying to understand, not that there was no resolution to the conundrum, and not that their epistemology is "inferior" in some way.

Consider that when a native culture has an origin story involving a specific place, regardless of whether we have believe that humanity evolved there, there is really no reason to doubt their culture emerged there and that that place has an important bearing in their.

I'm pretty sure that's what I would do.