You seem to be implying there is some kind of conspiracy to portray one particular group as bad while ignoring another. I don't think that's warranted, there has been plenty of media vilifying America's natives. There is perhaps an effort to correct the record: history was written by the victors, and it has taken far too long for us to realize the many injustices that were carried out along the way. Understanding what we lost (in this case, vast Bison herds) is important. These losses affect natives and immigrants alike.