Earlier quoted context omitted.
You're taking it a little too literally. The theory is that once a situation seems less maintained, people will normalize that state and allow it to decline further. It's essentially a slippery slope argument, though I do think there's a little bit of psychological truth to the argument. But I also think there's a really high cost for trying to keep things perfect.
The cost is in cultural adaptation, not police work. Singapore has a high standard of public appearance and behavior. It comes at a cost. But they did succeed in creating the social norm. Without that the police effort is endless.
As far as Singapore goes, I don't have a ton of experience there to comment. If their standards end up leading the police to proactively treat people like criminals, then I suppose I wouldn't like that very much.
Worth noting that Asian culture in general seems to have much more of a "compromise the individual for the good of the whole" component, though. Nothing wrong with that, but it's a poor fit with our cultural expectations.