I’ve never understood why people get so worked up about stuff like this.
Nothing changes within the narrative itself. In-show characters don’t acknowledge the character’s newfound darker skin tone. The character stays true to the original vision - except that their skin is darker.
I would be outraged if Dev Patel played an English knight and then was shown eating Indian food or wearing Indian clothes. That’s breaking the consistency of the narrative and the authenticity of its world.
But Dev Patel simply plays an Englishman - with English habits and speech. Nothing within the world is changed to match the actor’s skin color or heritage. Rather, the actor’s skin color blends into the narrative’s world.