I'm pretty certain that whatever the original culture is, it's been dead for some time. Probably a good thing. I can't imagine some ancient hunter-gatherer culture working in the modern day all that well.

But seriously... who the hell honestly says that if you are white, you should be ashamed of it? Sounds like a strawman to me. What exactly is the "white" heritage? I find a lot of interest in my Scottish heritage. I just don't think it somehow makes me special today that my ancestors wore kilts. I feel the same about all cultures. Live your lives for today, not for $#@%%@ yesterday.
No, I-AM, you do not get a cookie just because your ancestors, or people related to them, were the people in the right place and right time choosing the right option in history. And no one buys your crap about people not related to your ancestors deserving to pay for their ancestors' not being the ones in the right time, right place, and choosing the right option. We live today. If you have to use the padded "glorious past" of your dead ancestor's distant relatives to justify your "righteousness" or "right to succeed", then perhaps you should have stayed in yesterday rather than moving on to today.

__________________
"Man lives in the sunlit world of that which he believes to be reality. But unseen by most is an underworld, a place that is just as real... but not as brightly lit... A DARK SIDE!"
-opening from Tales From the Darkside