The more interesting question is where she obtained those sweet potatoes. The store, I know. No one grows sweet potatoes in Washington, D.C. But where did the store get them? For many thousands of years, the sweet potato was trapped in distant places in South America; it somehow made its way on boat travels to the Polynesian islands, and finally landed in Japan by the late 15th century.
Only once boating technology and capital expenditure for exploration grew to reveal the first signs of prosperity for the masses of people did the sweet potato make it to Europe via an expedition led by Christopher Columbus. Finally, it came to the U.S.
But this took many thousands of years of development — capitalistic development — unless you want to see this root vegetable as the ultimate fruit of colonialism and thus to be eschewed by any truly enlightened social justice warrior.