That's probably all the producers asked her about. I don't really blame her for saying something regrettable like that, especially if the producers kept at it all week.
Kinda like how they would keep asking Kayla about being homeless and gay, or Elina/Marjorie being European or Esther being Jewish, etc...
Can't remember who it was but a previous contestant said that the producers warn contestants in confessionals that if they don't give the producers something to work with then they can't form a winner's arc. So they feel compelled to say stupid things or play the game in fear of getting cut.
They only wanted Mariah to last as long as they could exploit the fact they had a Native American on the show, for the sake of "expanding the definition of beauty"
