"Should we help them" in one sense is a question we could think of in terms of absolute morality and I am under the belief that there is no such thing; and therefore in this sense we have no obligation to help these people. However, I'm sure if I saw them I would want to help them because I would feel compassion. That is me, though, and I cannot speak for what we "should" do in any absolute sense.

That being said, I think the real dilemma is not "should" but "how should" we help them, if we decide to do so. Trying to help in a wrong way could end up doing more harm than good. Plus, who is to say what's good and what's bad? What's good for a civilized society may not have a positive impact on this savage community. One would have to study these people and theorize on ways their community could be improved -- which begs the question, why wouldn't one of them be doing this already? You say they don't want to be helped (which is very plausible), but I can't imagine they wouldn't want to help themselves. Eventually someone would be born who has the brains and leadership to improve society. He may be worshipped as a God, who knows. Otherwise, they would probably die out as a race.

If I came along I would probably want to help them but I wouldn't know how. They would probably dislike my intervention because that's a rather natural primitive human reaction. I imagine I would eventually give up and get the hell out of there, and I wouldn't feel bad about it. It would probably be the most humane thing for both parties.