Of course you and everybody else gets it with Ariel. You just don't want to admit it because you don't agree with it. I'll say it, since nobody wants to, and you can virtue signal your horror and disagreement, and we can move on.
In the original, Ariel was a pasty white girl with flowing red hair. People connected with her, and part of that is the image. How she looks. Nostalgia. So while her race is a part of that, expecting her to look like that in the new movie isn't inherently racist. Even non-whites overseas expected to see someone that looked like the character they fell in love with 30 years ago. If the original Ariel had been dark skinned and they made the new girl look like the original Ariel, the response would have been the same.
And if you still don't get, imagine a live action Princess and the Frog with a white girl playing Tiana. The world would be on fire. And it would fail miserably, as it should. A big part of nostalgia is authenticity and being true to the original. Image is a big part of that. You can disagree, but that's just reality.