It is our job to uphold the law
The law and the police aren't something outside of society (or at least they shouldn't be). They are just some specialists that we as a country are employing to help us in achieving our ideal of how society should work. The job of creating that society in the image that we want is ours.
You wouldn't, I hope, ignore a shoplifter or walk past some teenagers mugging an old lady. How is this different?