By her telling, it’s more about stripping away the “sing-songy” bits of her natural voice. You can call it an “affectation” (I might just call it “acting”) but it fits the tone of the role. I don’t blame anyone who just doesn’t like the sound of it–seems like it’s similar to abhoring the crunching of snow or eating of a popsicle–I just have a mild objection to saying it’s bad acting or bad casting.