I’m white, and my and my partner’s families mostly do this in jest or to quickly grab attention because “Meredith!” gets attention in public much faster than “Mom!” does lol I didn’t think it was only a white people thing.

Edit: just generalizing, but I think it might be the idea that a black person wouldn’t do this under any circumstances? Whereas it’s joked somewhat often (at least by my black friends) that white people can get away with more “insubordination” in their families compared to black people. That’s my theory but I’d love to hear other perspectives lol