While I agree that Tolkien likely viewed the races of men, elves, and dwarves to be white, and a show that seeks to adapt his mythology while having a diverse cast will stray from Tolkien's vision, we run into an interesting problem: a LOT of money is being spent on this show. Amazon reportedly spent 250 million to acquire the rights, and another 500 million on the first season. The US Bureau of Labor Statisitics says that there are 51,600 working actors, and they earn on average $23.48 an hour. Assuming 2000 hours a year, that's $2.4 billion spent on acting a year, putting Amazon's current budget of $750 million at roughly a fourth of all money spent on acting. With this in mind, if Amazon were to only hire white actors, in order to be equitable towards those of other races, we would need to guarantee that $250 million went to projects with actors of other races, and those projects would need to be entirely multi-racial. If said projects were in abundance, than I wouldn't be opposed to an all white Rings of Power, but considering that the highest budget project with a majority multi-racial cast I can think of is Nope with a budget of $50 million (and even then there are still white actors), if a company wants to make a nearly $1 billion show, it is necessary for there to be at least some actors of other races. If the show had half the budget, or if there were more projects written by and for a black audience, then I would prefer that it is acted by only white people, but as it stands now, it makes sense for there to be diversity.