I agree that the author's assertion that "racism" is the only possible motivation for someone wanting a white, red head Ariel is incorrect.
But I also think that it is incorrect (or at least silly, and overly dramatic, to the point of dishonesty) to characterize a black Arel as amounting to "vandalism" of the story and as Disney having "zero respect" for Danish culture.
It's just a story. And Disney has already done a version that was faithful to the original in that regard.
But when a story is a classic, and hence, gets re-told, and re-adapted many times, it's okay to change some of the details in different versions. That's part of the fun. And we need to collectively learn to see it that way.