At some point we have to talk about how there's a high chance that the Ramayana is a metaphorically simplified story passed along history to celebrate the conquer, violence and subsequent cultural whitewashing (or 'unification') of the entire of southern India and Lanka under the mainland vedic religious narrative which persists till today absorbing all local folklore as parts of its tree.
I don't really have a moral judgment on that, all religious narratives are historical propaganda.
However, as relating to the above discussion, I think it's important to examine when the arya purush Shri Rama pushes southward, he encounters opposition from South India under the rule of the kingdom of Kishkindha (modern day Karnataka). Curiously, the south indians are described not just as dark-skinned but also monkeys who looked virtually indistinguishable from each other. This is despite them clearly being humans in every conceivable way and having their own cities and culture.
After conquering said monkey tribes, as we all know, Ramayana goes further southwards to encounter and conquer the dark skinned rakshasa king of Lanka as well as burn down their entire city and celebrate this as some sort of glorious thing.
It's important to note that these monkey tribes and demons can have all sorts of admirable and beautiful qualities and can even join and become part of Rama's army but despite that they are never described as human unlike all the mainlanders mentioned in Rama's early life, regardless of class/caste.
It's easier to propagandise yourself as benevolent civilisers when you portray your darker skinned victims of battle as sub-human or animalistic, foundationally, regardless of character.