In the 12 years since we've only had one incident. In 2002, a member of a sport shooting club (one of the few categories of people allowed to own handguns) opened fire in a Monash classroom. He killed two people and wounded five others, but since he could only manage to acquire handguns he had to switch weapons and was tackled to the ground. No doubt things would have been a lot worse if he'd had access to something with a larger magazine. We tightened laws on handguns after that as well.
I find myself surprised that an otherwise relatively pragmatic people get so blind to the consequences of readily available firearms. I don't have any ideological opposition to guns - in fact, I quite like them - but if someone told me that yoga was involved in every killing spree in the last decade it would be pretty silly not to take a serious look at whether ready access to yoga is worth the cost.