Kevin, its cultural.
You have to remember, the US isn't a country, it's 50 countries. What we live with as "normal" we assume the rest of the world has as normal. About 1/3 of the Americans on this forum live in states that allow supressors, short barrled rifles, AOWs (sawed off shotguns), concealed carry with minimal licensure, and many other liberties. When your ten year old can run down to the store and buy a night vision optic, come home, and shoot coyotes with it, you just assume its like buying a toaster. Most have no clue that you can't transport this stuff to other nations as its no big deal in many locations.
It's not arrogance at work here, it's ignorance. Most people just don't know what is acceptable in other US States, much less in other nations.