My sister laughs at someone’s so-called shortcomings when she meets them. How should I persuade her?

It is best to find a suitable opportunity and do it naturally. The truth is nothing more than: there is a shortcoming and a longing, no one is perfect, and no gold is pure. It is very cliché, but this is the truth. There is also an indecent saying, crows laugh at pigs for being black, but what the pigs see in their eyes is black crows without a single white hair. In summary, this sentence made her understand and strive to be "kind to others". She can always see the goodness of others in her eyes and always have a sunny day in her heart.