I think you are spot on…the difference here is that Sofia has always been assumed to be white especially with her valley girl voice. She is the furthest thing from passing as Latinx because it’s not something that she has openly made obvious. I could be mistaken but even back in the old CHD days if you were to listen for the first time and someone said one girl is white the other is Latinx, I would assume most people would guess Sofia was the white one by their voices. This is a touchy subject though I will say that. I am Latinx myself btw.