I think, Greg, it's because so often in the past the Indian (and yes, they call themselves that so I will too) bodies and graves were despoiled that they're more than a little annoyed. The Smithsonian Institution had (and still may have) hundreds of bodies, taken from despoiled graves, battlefields, and other places, collected during the 19th and 20th centuries in the name of science. Other places had smaller collections.

Granted, these collections helped and still help the science of anthrometrics and others, but mostly the bodies just lay there in drawers. So the Indians thought it high time that the bodies of their ancestors were returned to them for reburial.

Well, this is okay, except that some nations (such as the Navajo) didn't want the bodies back (goes against their traditional religious beliefs). Other Nations no longer exist at all.

The biggest problem doesn't seem to be that the bodies were studied, but that they were taken and never returned (until recently). The high-handed, uncaring, unfeeling tactics used caused great and deep resentment against the anthropologists which the current crop of anthros are reaping.

That's sort of it, in a nutshell and very simplified. Racism played a big part in it, as did the conqueror attitude of "to the victor" and a heavyhandedness beyond belief.

It can, and is, being handled differently today. But only ways and old ideas are hard to change, especially when they have been cemented by so many other, similar, things -- destruction of Indian languages, destruction of a way of life, forced education in the White Man's ways, even (during the 1950s) a misguided attempt to "integrate" the Indians into the White Man's cities and wipe out the reservations completely. Oh yeah, I'm convinced that these were all done with highest and purest of motives at the time, but they were wrong -- they tried to make indigenous people over into the image of the conquerors. That will breed resentment every time!

Check out, too, the case of the Indian Trust Funds. The Bureau of Indian Affairs seems to have "lost" an awful, awful lot of money that was due to the various Indian nations and individuals....

Please note that this is my view of things, and nowhere near complete. I'm just a librarian who works on the edge of the Shoshone-Bannock rez and who has worked on edges of other Nations, not a specialist in this field by any stretch. The nuances are great....