On the way here, Xiao Qian had been strategizing every step, she has thought of everyone's bottom line and their inner fears.
The reason she didn't suggest to Shi Touyu to ask these people to release them was that she knew they would never agree.
When people are impoverished to a certain point, their perspective of the world alters. They reverence gods and spirits, but if it's for money, they would dare to kill even them.
Their respect for gods and spirits is not born out of heartfelt belief, but fear and for personal gain. When the fear induced by the spirits exceeds their threshold, and they can't achieve their goals, they simply stop believing.
To these people, gods and spirits are all commodities for trade. The faith of the least privileged people is solely based on utilitarianism.