There's a fundamental difference between embellishing your backstory, and creating a whole character - whose shtick since about 1960-61 has been based on being of an ethnic background. All the activities she took part in for being of indigenous/Indian extraction, all the awards that should have gone to actual real indigenous acts - it was all a charade. Though obviously she believed in the causes she was promoting.

if I ever watch 'Soldier Blue', the experience will never be the same hearing someone supposedly authentic, as a voice representing the Indian, who actually wasn't. It will still be a great song, but the awareness is now there.   

No-one can take away BSM'a huge cross over pop/folk songs... 'I'm Gonna Be A Country Girl Again', 'Until It's time for you to go', 'Up Where We Belong' 'Universal Soldier' etc. Great American songs, which deserve lifetime achievement awards galore. But the indigenous act awards she got are now soiled. Fine as an honorary representative, and some have claimed BSM, was 'adopted' into their tribal culture.. but it was a falsehood to claim her physical lineage as being from that source. Also there is something thoroughly sordid in threatening family members for exposing the truth of her background, instead of just coming clean about it.