That was just weird, huh? Well, I can tell you from experience that a lotta Japanese folks perceive a lotta overseas place as the wild-wild-west, especially the U.S.
Just about every Japanese person will also know about a story where an exchange Japanese student got shot trick-or-treating in Halloween. Some nutjob screamed out "FREEZE!" and when the kid approached the nutjob's house, but the kid heard it as "Please" - and translated as "Please go ahead" in his head. That's because the Japanese would say something like "Please" (douzo) to give permission to folks to do variety of things. In English, it'd be something like "Please (fill in the blank)". Then he ran in the house, and of course, he got shot.
I tell you, EVERYONE in Japan knows this story, and believed that it potentially could've been avoided if he had better grasp of English.
Reasons like this is probably why videos like this exist -> Just fueling the fear of foreign lands in Japan.
To be fair to the Japanese, I've also come across many other nationalities (Koreans, Brits, Canadians, South Africans, Ozzies) that have the same type of stereotype about the US, though not quite as extreme as the Japanese. With so much violence you see in Hollywood movies and extreme violence all you hear about in the media, it's not hard to see why.
Edit: Okay, just did a search on the news, and I got some interesting point that shows the other side of the story, and how the media made this completely one-sided and sensational.
http://www.blogd.com/archives/000124.html