If the 19th century Native Americans were a bit rapey or murdery by modern standards, that shouldn't affect how we treat their descendants today. This argument

If the 19th century Native Americans were a bit rapey or murdery by modern standards, that shouldn't affect how we treat their descendants today. This argument is bad because it means well-meaning historians feel they need to whitewash the history of Indian tribes as noble savages, just to get the reaction they want today.