Typically you see under-enforcement of crimes that have direct victims and real impact on people's lives - property and violent crime (say, a stolen car, or stolen bike that leaves the victim unable to get to work/child care, or the victim injured and unable to work, if only temporarily) that directly impact a person's life...and over-enforcement of general "orderly society" crimes and regulations that don't have a direct victim or impact one people's lives.
For example, you'll see cops take 20 minutes to respond to calls of domestic violence, which might come down to being short staffed.
But isn't it strange that every patrol cop in the neighborhood never fails to make sure to check that the corner sausage cart vendor and ice cream van have every single permit in order? And how there's always time to stop someone for a non-functional tail light? And to stop random dudes for pat-downs?
While in the US they have to come up with a billion bullshit reasons to stop someone which mostly impacts poor people in bad cars.
it's not that surprising. I'm sure malice is part of the explanation, but it's also just easier. the ice cream van either has the permit or they don't. they're not going to run away. in 30 minutes, the officer gets to add another citation to the monthly tally. it's a nearly certain outcome that takes little effort.
the stolen car or bike is already gone by the time the officer shows up to the scene (if they bother to). it takes an indeterminate amount of time to track down the stolen item, and even more to gather enough evidence to actually charge someone. it sucks, but most people who are evaluated on metrics try to avoid spending a lot of time on tasks where they might come out empty-handed. it's a hard organizational problem to incentivize this sort of work.
If you work a low-end shift job and miss a shift, you're likely to get fired almost immediately, or put on some sort of suspension, or otherwise punished via poor shift assignments and the like. At the very least, you lose income for the shift, and that is likely a substantial amount of money for you. The "court fee" is a substantial amount of money to you. You end up with a public defender who has little influence with the other officers of the court - the judge, the DA, etc. They have a docket a mile long for that day and needs to triage their time and resources, so they push you to plea out so they have time for the guy who is facing a felony or even capitol charge. If convicted your choices are jail or fines, and the fines might be days or weeks of pay you don't have.
If you work a professional job, you have "personal days" you can cash in, your employer provides you with things like free legal assistance via EAPs - or you probably already have established professional relationships with at least some sort of attorney, who you can afford, and who knows someone who knows the judges and DAs in the district you're going to be appearing in, and maybe the whole thing just goes away. The court fees are a rounding error in your weekly pay. And the laws are all "jail time or X dollar fine." So even if you're found guilty - the fine is a rounding error to you.
