The basic fallacy goes something like this:
If you spend your time thinking about violence or practicing violence, you're more likely to engage in violence.
A more constrained, focused, defensible claim can be made about children who grow up witnessing violence within their household and among their role-models. But the general claim encompasses shooting sports, hunting, martial arts, contact sports, and media depictions of violence.
This fallacy is often the foundation of arguments against violent books, comics, movies, television, and video games (I'm looking at you Dave Grossman). I'm sure I'll hear it again when virtual/augmented reality really catches on in the consumer market. Despite the easy availability of "violent" media to everyone, the increased exposure has not accompanied even faintly corresponding increases in violent crime.
While the argument is superficially plausible, there's no empirical evidence – in the real world, outside of a laboratory – that it's true. On the contrary, there's compelling, if informal, evidence that the more educated a person is about real-world violence, the less likely they are to become involved in it. When I started watching the following TV pilot, I was a little skeptical of L.J.'s ability to internalize the value of fight avoidance in just three short days. I shouldn't have been!
Lest you think this is limited to hand-to-hand training, or only anecdotal, here's another statistic that has always impressed me. Tom Givens instructed tens of thousands of people in the Memphis area from 1996-2014. The last tally I heard was that 60-some-odd Rangemaster students had been in deadly force encounters. Except for two (who chose not to carry their gun that day) every other student survived. Those are impressive numbers for any self-defense school to put up, but they're not the most impressive number. Based on the number of students Rangemaster taught and the prevalence of violence in Memphis, you'd expect three to four times more students to have been in fights for their lives.
Shooters are often portrayed as macho, aggressive, or cavalier about life and death, but that runs contrary to a bunch of Memphis residents, carring a gun on a daily basis, who more successfully avoid violence than their neighbors. Although I can't divine the motivations and thought processes of all those people, nor peer through history at all the might-have-beens, I feel qualified to speculate a little based on my own experience.
The more I understand the consequences of violence, the less likely I am to engage in violence and the more strenuously I seek alternatives. That doesn't mean I've become pacifistic or won't fight when I can't avoid it. But a well-developed sense of the severe and permanent physical, legal, and social aftermath naturally leads me to avoid violence whenever possible.