But surely the locals were upset that they were losing money, not that the money they lost went to city hall. In other words, I doubt they'd be relieved that their money was going to corrupt policeman rather than the city government.

If all the available money for fines was being extorted from drivers by corrupt cops, the city would have to get money another way, or cut services. This would likely upset the people of Ferguson even more.

Another way of looking at it is, what wealthy, safe, clean, productive societies regularly engage in bribery?

Cutting services is awful and harmful but it's not dangerous in the same way that using heavily armed police as emergency tax collectors is. It's bad but the depressingly stable self-perpetuating kind of bad, not the unstable riot-causing kind of bad.

My point is that, in a bribery society, the police would be collecting the tax anyway. The difference is that they would keep most or all of it for themselves personally. Thus, all of the anger would be there over losing money, plus anger at the injustice of having to bribe corrupt cops, plus diminished services.

I also think cutting services can be dangerous. For example, a service to feed the elderly, inspect water safety, maintain roads, deploy police to prevent or reduce crime, after school programs for disadvantaged teens who might otherwise get into or cause dangerous situations, etc.