Why did the citizens of Poker Flat suddenly decide to clean up the town?

The citizens of Poker Flat decided to clean up the town due to a growing concern over morality and social order. They aimed to expel individuals they deemed undesirable, including gamblers, outcasts, and those associated with vice, in an effort to restore their community's respectability and moral standards. This decision reflected their desire to return to a more virtuous way of life, influenced by the harsh realities of the surrounding environment and the challenges posed by the gold rush era.