Online and at real life militaria shows, well preserved legimate Japanese katanas fetch thousands of dollars. Even authentic Imperial Japanese Army bayonets go for hundreds of dollars. Also, for each rare family treasure, there were thousands of officers katanas' made in government armories before and during the war. As the war went on and materials became scarce the quality declined precipitously, and a lot of the later swords weren't even at the level of a gardening tool. They used stained wood for scabbards. When the Americans occupied Japan in 1945 they siezed mountains of them from the IJA. And of course because good examples fetch so much money, there are many, many forgeries, just as there is for all collectible militaria. It is impossible to know if the swords you saw were reproductions that weren't even made in Japan or war trophies taken on the battlefield, but if the seller had them in a pile they're not really valuable to anyone. The good ones go in a vault. So when you say that you want people to understand where those swords came from, the fact is that you don't know. They just look like something important.

No one collects an object like an antique sword unless they have a full appreciation of the history of the object and respect for the craft of making it. I would wager that anyone who collects Japanese edged weapons knows a hell of a lot more about Japanese history and culture than the average American, and I believe having knowledge about other cultures is supposed to be a good thing.

WW II vintage Arisaka 99s are not particularly good rifles, and the late war ones were poorly made, but they still go for 500 bucks. I wouldn't dare to shoot one, even assuming you could find ammunition for it, but people still collect them because they like World War II stuff. The Imperial Japanese military was pretty evil, but at least their WW II militaria doesn't have swaztikas on it.