No shit a shooting club is packed with people with a gun.
Doesn’t mean Australia is packed with guns just because you see a handful of idiots down the road, that is not representative of the whole population. As you said heavily regulated, there’s virtually no guns besides farms and the club down the road from you. Quick search puts AU at 14.5 guns per 100 population. Quite low in the list and well below civilised places like Canada, Switzerland and many eu countries.
What people on reddit and lemmy don’t seem to understand is that the shock caused by ONE mass shooting, port Arthur, and the policies introduced as a consequence shifted a country that was similar to the US in terms of gun ownership to become similar to a western European country. Ie guns are virtually non existent (unless you leave next door from a shooting range, apparently that needs to be made clear).