Well there are people who think Momoa looks more like Namor than Aquaman.
I would say race isn't an issue for fictional-race characters. In the MOS universe Atlanteans look like Hawaiians apparently and Aquaman is half white and half Atlantean played by a guy who is half white and Hawaiian. You could argue Atlateans looked black, or blue, or whatever since they are a fictional race.
It's different than saying in this universe white people look like black people.
Although Nick Fury is black and people are fine with it for the most part. Who knows? Maybe Sam Jackson as Magneto who dealt with lynchings instead of the Holocaust would still sell tickets (even if he was fighting The Rock and his optic blasts). In fact I want that as a "What If?" story.