I disagree with Bingo that a history of repression needs to be present in order for racism/speciesism to occur, however I still don't believe Leia's "walking carpet" comment denotes an incidence of either on her part.

For example, what if Han had been the one walking in front of Leia and she had said, "Would somebody get this self-righteous dolt out of my way?" Or what if Luke had been the one blocking her and she had said, "Would somebody get this undersized pipsqueak out of my way?" Such comments, while rude and insensitive, are not racist, nor would they be interpreted as an attack on anyone who is unintelligent or short. Rather, they are personal attacks on the individual. The "walking carpet" comment, then, should not be seen as a speciesist comment on the entire Wookie race, but rather as an affront towards Chewbacca alone.