Think of it this way, Isabelle assumes that these people don’t know better. She sees them as some primitive tribe, a step from Neanderthal.
She doesn’t complain about the various things they do because she assumes they are not accustomed to modern life.
She assumes where they come from they have pit toilets, have to carry water, and cook over a wood fire.
Hence she doesn’t complain about anything they do.
They may think she is ‘afraid’ of them, they may think she isn’t ‘bothered’ by them.
They never realise her true opinion of them.