Until we have robot police officers, there will always be a human in the loop. But right now, there's a whole category of "drunk and disorderly" / "breach of the peace" kinds of laws that are ~100% up to the discretion of a police officer to enforce. I won't say you CAN'T have it any other way, because I can imagine alternatives like "don't have those laws", but I will say that you don't WANT to have it any other way.

Elected lawmakers and courts.

They could at least address that the man and woman on the street would easily identify as people who need to be put in a paddy wagon. Leave the unsure cases alone. Get the obvious ones.