Considering this claim of hers dates back to the 60s, I don't really think you can think of it as part of a growing trend now.
It was during the Hippy era were that sort of thing was cool and gave you cred. Probably more so than now where it just gives you access to more government funding.
From the article
"
Sainte-Marie’s career began just as the hippie movement was emerging across North America. It was characterized by a rejection of Eurocentric culture and an embrace of Indigenous spirituality, according to Teillet.
“The hippies are in the process of throwing out the traditional churches and adopting spiritualism, and they reach out to Indigenous people to adopt some of their ways.”"
"
Sainte-Marie’s growing fame in the 1960s and 1970s coincided with a critical moment for Indigenous issues in the U.S., said Prof. Kim TallBear.
“This is a moment when you see Native issues are beginning to come more into the public consciousness, as you see these red power and Black power social movements … where people that have been silenced for so long are suddenly in the news.”
TallBear said Sainte-Marie’s “long black hair and this kind of exotic sort of image she’s cultivating,” combined with her claim of being Indigenous, “greatly elevated her career and her visibility.”
“I’m not saying she’s not talented,” said TallBear. “But she is very much this representative image of a Native American singer.”"