What about "easily available" instead of "freely available"? Apparently, gun shows are one way for easy access to such weapons be people that never should own any gun in the first place.
WRT 'easily available'- that's a good description.
You need to find out that well-run gun shows aren't the free for all that you think they are. I'm sure some are held in rural places in barns, without any public knowledge, oversight by law enforcement or using applications for sales but if the sale is private, an application isn't required. That could change, but I don't see our Congress doing anything about it. You can say "Vote them out", but you also need to realize that if you want to make change via elections with your country's population, this would amount to a grassroots effort. With the lack of education and apathy here, it's all talk, no action.
I know of people in Middle America who gather for an annual event on a large property that has people bringing legally-owned fully automatic weapons, many are vintage and from the last 200 years. These weapons include Thompson sub machine guns, Browning Automatic Rifles (referred to as 'BAR'), etc. No crime sprees, nobody shoots anyone because of an argument, no guns are stolen from unlocked cars and no firearms are unsecured. Most of the people at these gatherings are former military and they just like to compare their guns, have a cookout and hang out with friends.
Locally, people may get together with guns, but if it'snot a real gun show, they're not legally in possession and they fire them for all kinds of reasons in populated areas. Like last night, when I heard a volley of 7-8 shots at about 8PM, likely fired less than half mile from my house. This is common and it's in Milwaukee, but my house is about 150 yards from the border, in the smaller city adjacent to Milwaukee.