Traffic laws don't exist for their own sake. Their primary purpose, above all else, is to keep drivers safe.
Look, we'd like to believe that, but we know that some of them are bullshit and they're only used to make money.
By and large, I have to sadly agree. Even so, at least in the state where I live, we have prima facie speed limits, which more or less means that it's not illegal to drive over the speed limit if one can demonstrate that doing so was reasonable. A handful of other states also have prima facie limits or else have them for drivers who were caught with speeds that weren't excessively beyond the posted limit. So that's at least a small acknowledgement on the part of the legal system that these laws aren't just there for the sake of frustrating us.
But yeah, uneven enforcement is a major problem. I'm all for letting people off the hook with a warning or letting people off the hook when it simply makes sense, neither of which machines left to themselves understand, but when someone is being unsafe, it doesn't make sense. Thankfully, the laws about the passing lane being used for passing are actually enforced on the stretch of road near here where it's in effect, and it's helped to significantly improve the flow of traffic along that stretch of road, since previously the disproportionately large number of college students in this area would demonstrate their inexperience on the road by not using it how it is supposed to be used.
I'll routinely see good cops like those going 10-20 mph over the posted speed limit, along with the rest of traffic
If there are good cops, why don't they do something about all the bad cops?
A fair question, but let's turn it around to get some perspective: if you are a good person, why don't you do something about all the bad people? Even if you were doing everything in your power (which you may be, for all I know), what measure do we use to determine your goodness? How hard you tried? How successful you were? I think the only answer is that good people aren't always in a position where they can do something about the bad people, and even if they are, we don't have an inside view to be able to tell whether the persistence of the problems is due to them doing their job poorly or because of other problems that are beyond their control.