Sometimes, the word black does not have any racial meaning. The name "black Friday" has two possible origins: 1) The sidewalks are black with people on that day, and 2) Merchants' ledgers are "in the black" (profitable) on that day, instead of "in the red" (losing money). Given this, why rename it? In any case, "black Friday" is not an official name, but rather, a folk name. So you can call it anything you want, and the challenge is to get others to go along with you.