Since you lack reading comprehension, let me emphasize the relevant part of the note for you:
You see, guns are mostly illegal in England, just as swords are mostly illegal in Japan, so there's a direct comparison to be made in that most have never seen one and anyone pulling one out in company is probably breaking the law brazenly and with the potential for physical harm, so it is shocking. Whereas no part of that comparison works for an American seeing a history book.
I see you just can't help yourself, you keep ticking those stereotypes like a champ. This time it's "American sees something rare/unexpected, he concludes: crime!". And of course he assumes everyone outside of 'Murica functions like that. Newsflash, no we don't. Seeing a weapon in public might not be an everyday thing, but only the mentally unstable immediately jump to "probably breaking the law brazenly and with potential for physical harm", when said weapon is in no way being used to threaten anyone. So yeah, if it's not poor reading comprehension, it's a warped mindset. Badly, too - from your last sentence it's evident you realize that something's not right with your take on the joke, but still can't reflect.
By the way, you were saying something about language earlier? Now you use terms like "mostly illegal"? Sigh... Let's add the "Americans are utterly shameless and every accusation of theirs is in fact, a confession" to the list then... Anyway, they are not illegal, you just need a permit, same way as in Japan. Don't let that stop you, though. You're on a roll.
