I think a lot of Sektor's attitude gains an interesting dimension when you realize she's basically the Lin Kuei's equivalent of Madame Bo: She's their primary instructor. Even when the previous Grandmaster was still alive, Sektor was still teaching trainees like Tomas and Cyrax at the time. It gives some of her lines more weight, like her bewilderment that Kung Lao was allowed to teach (and we know how THAT ended, from his ending). For all her smugness, Sektor does know what she's talking about.