Well that’s kind of funny. You’re right that white people cooked up her image. And they did so specifically with the idea that she would fit that stereotype of the older slave woman who has always worked in the kitchen, and is happy to do so, and because of that she’s really good at cooking.
By the way, the word “aunt” was not used to be respectful, but rather specifically to be disrespectful. That particular nuance has faded over time, but the history is real, and once you learn it you can’t forget it.
The sad thing is, you could have inferred this without looking it up. You could have asked yourself why they didn’t use a cartoon character of a white woman, with a white sounding name. The fact that you didn’t, and that you didn’t bother doing a web search, shows how much you want to avoid seeing racism in the modern world. But just because you don’t want to look at it doesn’t mean it doesn’t exist. Reality is not that kind, my friend.
Finally, don’t take my word for it. Ask the company itself why they changed the name. They have documentation on the subject.