Even though they weren't privy to the whole truth, they could fill in the blanks with their own imaginations.
In their minds, Xia Xinghe had to be a less than stellar woman.
If not, why would her marriage to Mubai only last for three years?
Mubai is such a perfect, saintly man, if even he couldn't stand her, it goes to show how horrible his ex-wife must be.
Now that they saw that she hurt her sister with 'their own eyes' and still dared to hold herself in such high regard, it was hard for them to believe she was a good person.
None of them knew, while Xinghe was being supercilious, it was specifically aimed at the couple's acting.
She felt embarrassed on Wushuang and Chui Ming's behalf for their crappy acting chops. She refused to entertain the duo's laughable performance.
But in people's eyes, her lack of response and emotion was misconstrued as egotism.
People have issues against women that think too highly of themselves.