Because African art is no longer something White people who look like that have

They had flip-flops like that in 1959??

Yes.

"The modern flip-flop became popular in the United States as soldiers returning from World War II brought Japanese zōri with them. It caught on in the 1950s during the postwar boom and after the end of hostilities of the Korean War. As they became adopted into American popular culture, the sandals were redesigned and changed into the bright colors that dominated 1950s design.[10] They quickly became popular due to their convenience and comfort, and were popular in beach-themed stores and as summer shoes."