I had an encounter with a pair of New Orleans cops that was pretty terrifying.

I would say that most people have had little or no experience with violence, outside of perhaps the occasional dominance contest (mostly the realm of males under the age of 30 or so).

There is a gross difference between a dominance contest and predatorial violence, and until you have experienced the latter, you really have yet to sample the full emotional gamut of human fear.

As an aside: I tend to avoid the word "criminal" in cases like this -- it's a loaded word with a lot of connotations -- and stick with "people that have never experienced predatory violence" or "people that have never encountered a predator".