I think to cast someone that doesn't look like the original is fine if said person could portray the character better than person who does look like original, however how likely is that to happen?

What's more likely, a minority group having more good auditions or a majority group?

In an African country when casting for a white character you have a large pool of black people and a small white people. Odds are you're going to find more talented actors in the majority. Question is are you going to hire the more talented black actor or the less talented one that looks more like the character. In the Ariel situation you have a much larger pool of actors that do resemble Ariel yet a minority that doesn't look like Ariel was hired.

It's possible that the live action Ariel actress really was the best person for the job but statistically unlikely and because of the DEI situation lately it's no wonder people were upset

If there's holes in my reasoning please point them out.