Might Dietz have invented his "Indianness" in order to be able to play ball for Pop Warner?

Here's the situation. The author is referring to the controversy surrounding the offensiveness of the Washington team name.

The team got its name in 1933 from the late owner George Preston Marshall. He wanted to pay tribute to the Indian ancestry of his coach at the time, William "Lone Star" Dietz. But a revealing story published two weeks ago in the Baltimore Sun, which focuses on new research by a California multicultural studies professor, discredits Dietz. Turns out he was a white man "who began taking on an Indian identity as a teenager and ultimately seized the past of a vanished Lakota tribesman and made it his own." The coach was convicted of misrepresenting his identity on military draft documents. So there was no American Indian for which the team was named, just a perpetuated stereotype of the time.
Mike Wise, Sept 17, 2005 Washington Post
"Questionable Naming Rights"