(Prompted by my friend Jason Mankey's Facebook share of David Frum's piece over at The Daily Beast; you can read that for the other side.)
The fatal shooting of Chad Oulson by Curtis Reeves, a 71-year-old former Tampa police captain, over a dispute about texting in a theater certainly illustrates something disturbing about American culture...but perhaps not what advocates of firearms prohibition think.
To be sure, texting and throwing popcorn should not result in someone's death.
And it is true that foolish people sometimes bring guns into situations that would not be dangerous if the fool had not introduced a firearm into the equation.
And it's true that the opt-cited statistic of 2.5 million defensive gun uses per year may be way off -- it is highly controversial.
On the other hand, for example, a woman who carries a gun in her purse for protection because she is frightened of an abusive ex-paramour, should not face jail time for exercising her right to self-defense (which necessarily includes the right to take reasonable precautions against rationally apprehended danger). Because it's also true that guns are used by innocent people to protect themselves or others in legitimately dangerous situations.
How often? The error bars are huge, because many cases are never reported to the authorities. (Why open yourself for possible prosecution from an overzealous or hoplophobic prosecutor?) The lowest figure I've seen in the literature is 64,000 defensive gun uses a year. That's likely an under-count given the methodology: "I'm calling on behalf of the federal government, and I'd like to ask you some questions about crime. Have you ever pointed a gun at someone?" I exaggerate somewhat, but surveys conducted on behalf of governments about behavior with legal implications are going to see an under-report of that behavior.
The next lowest estimate is over 100,000, based on a similar method of questioning.