Why does Dee think that Mama and Maggie don't understand their heritage in "Everyday Use"?

When Dee/Wangero tells her mother, "You just don't understand...your heritage," she implies that hand-made artistic items in their family should be put on display instead of being used.

Even before Dee became involved in the Black Nationalist movement, she rejected the conditions under which she was raised. Nevertheless, she promised to visit her mother and sister no matter where they might live. But Mama and Maggie are not prepared for Dee's new name and her boyfriend. Dee has rejected her birth name, which comes from Dicie, a family name traceable to the Civil War, in favor of Wangero. Now, on her visit Dee wants to take back with her the butter churn of her grandmother, benches made by her father, and quilts made by women in the family.

Because the value of the quilts lies in their functionality for Mama and Maggie, Mama snatches the quilts out of Dee's arms when she tries to take them. She then hands them to Maggie. Dee exclaims,

"Maggie can't appreciate these quilts! ... She'd probably be backward enough to put them to everyday use."

Maggie does, indeed, use them. Moreover, she appreciates the quilts for their beauty, which lies in their functionality--something that Dee does not understand.