This is true! But there is also the fact that the US established their country (war of independence) and and to a great degree their identity (the civil war) through armed conflict. So the root connection to firearms has a different flavour. I can see what you mean with the individual being held to account. If Australian's are unhappy with the individual in leadership there can be a pretty quick change. Where in the US there is much more hesitation to toss a party leader when things look rough.