If cops couldn't let thousands of people off per day on minor things, those minor things would cease to be illegal and our legal code would finally have some semblance of sanity.
You're right. If a cop sees you step outside the crosswalk at an intersection, he should have NO choice but to cite you for jaywalking, and generate all of the paperwork and costs involved, whether or not the reason you stepped out of the cross walk was to avoid walking through a big puddle of hydraulic fluid that was just spilled by a trash truck. It's situations like that where a cop's body cam might very well record such an infraction, and in the name of ridding society of any potentially abused judgement calls, we should use that technology to make sure that everyone involved toes the line, literally and figuratively. We can't have judgement calls! Your judgement call that we shouldn't is good enough for me.