As usual, the hoplophobe uses projection to legitimize his or her fears. Since they would exhibit so little self-control, they assume that everyone would be as out of control. Nevermind that her daughter was in very real danger of becoming this guy's plaything, she's more wrapped up in her irrational fears. And those fears make her want to lash out, but not at the guy who actually threatened her child.
Instead, she's going to lash out at anyone who might have had the courage to take a firearm and actually defend themselves against this guy. Since she feels inadequate as a result of her self-imposed helplessness, she wants to make sure that everyone around her is similarly helpless. Their ability to defend themselves is a threat to her. But of course, the real threat to her was close enough to smell; not some imagined phantom of what she'd have done "If I'd had a gun".