imho never saw this as a valid criticism/caricature of liz
most every family has some oral tradition and history that is passed down. there would be no reason for her to have doubted those traditions passed down to her.
she was from - as she's described it - 'scratching the walls of being middle-class,' or words similar.
her inheritance was that oral tradition of her family.
commercial dna tests have been around for less than ten years? ancestry sites and research trendy for maybe the last twenty?
it's silly to bash her on 'faux'