I won't go into how I view remains but you mention the Vikings, Celts and Romans- how many people are Viking, Celt or Roman? I don't mean decendents I mean of those, still here and praticing the same religion, tongue, etc. .
My Nation is alive and well and must deal with these grave robbers today. I know the peoples of Chaco may be unknown but this goes on in other tribes as well.
I am not an expert on this, and I simply wanted to point out that I don't believe people are singling your group out particularly, although I grant that if it were MY ancestors' cemetery being studied, I might have a less dispassionate view of the whole thing. So I guess you have made a good point.
I have a question: do they keep skeletal remains permanently, or simply study them and then rebury them? I think most information could be gained photographically and with X-rays, and then return the body to its burial site. (What am I thinking...there are Egyptian mummies in almost every large museum in the country. Nevermind.)