1. Let's not forget that universal statements can be refuted by a single anecdote.
A: "All apples are red"
B: "This apple is green."
2. Mythology works with universals. Perfection. Perfect heroism, pure villainy.
3. A single anecdote destroys, logically, any mythology.
But after the denial of anecdotal veracity comes the true scotsman to declare the bad appleness of the imperfection.
In any case, if you find yourself linking to anecdotal evidence disproving the existence of the mythologized cop, troop, etc., you're probably right.