That's how I see Darcy too: until Elizabeth turned him down, he felt the duty to be kind and polite to two sets of people: his friends and equals (not a very large group), and those who were distinctly his social inferiors (servants and tenants). IMO he didn't have much use for those who were somewhat below him in rank, but who didn't need his approval, help or protection. BTW, the first time I read "Emma" properly, I felt that she and Darcy must be twins separated at birth! ;-)