Bitch read countless people, used to take part in accidental amusement, so ruthless; It's meaningless for an actor to pretend a thousand kinds of horns and say a thousand kinds of plays. In fact, it is an extended metaphor for these two professional characteristics. In ancient times, these two occupations were considered as the most humble occupations, and they were at the end of the road. It is not surprising that literati loved to use them as word games.
Bitches and actors often take part in accidental amusement, wear masks to show people, and sacrifice their dignity and soul for profit. Over time, they lost their sincerity and became walking dead. Therefore, bitches and actors are actually heartless and meaningless, because their choice of environment and the concept of advocating the supremacy of interests lead them to become like this.
This sentence also reflects the demonization of artists by ordinary people in the old society while mocking powerful people. "Bitch is heartless and actor is meaningless" is a derogatory term for artists by the general public in the old society.