Sorry, I didn't articulate my first point well. The shooter in the Port Arthur massacre cited the school shooting in Dunblane, Scotland, as an inspiration for his crime. That happened the month before Port Arthur, and was heavily publicized in the month leading up to the Port Arthur shooting. The harm is that, by the admission of a mass shooter, the publicity surrounding another mass shooting inspired him to commit another one.

Ah, but it IS about the tools they use. That was my whole point regarding Australia's ban on automatic and semiautomatic rifles following Port Arthur. The ban on these types of weapons has correlated to a dramatic decline in mass shootings, because ready access to those types of weapons allows you to shoot lots of people at a high rate of speed. The after incident report of the Port Arthur shooting showed that the perpetrator killed almost a dozen people - a third of the death toll of the entire incident - within the first thirty seconds of the attack. Why? Because the shooter had a very accurate, high-rate-of-fire weapon carrying thirty or more rounds in a highly enclosed space. (Most of the people he shot were less than fifteen feet away.)

Now, would the incident have had the same death toll if the perp only had access to, say, a handgun? Possibly, but I doubt it. I know from my own experience with firearms that a rifle is substantially more accurate and holds way more ammo.

Australia's ban and reaction to this incident makes perfect sense to me, and two decades of empirical evidence seem to suggest their policy choice was absolutely the right one.