Most of it is complete ignorance over US gun laws. People elsewhere in the world are told Americans can buy whatever ridiculous ordinance they want, with no effective checks and they believe it. They don't know the story of gun legislation, and how full of fail most of those efforts have been, nor do they know about the issues with poor enforcement of existing laws. They just think you guys all be crazy.
Anecdotal evidence supporting this: When I was studying in Japan, some of the Japanese students asked some of the American students (I was not part of this discussion) if they had ever been in a gunfight, as if this were an everyday occurrence for most Americans.
