1) A lot of western culture comes from the same points of origins. France, Germany and Britain may all speak different languages, but we all use the same alphabet, and have invaded each other numerous times over history. America is a separate country from Europe, but it was settled by Europeans who brought their languages and customs with them. This means that there's a lot of cultural similarities among Western nations. Despite our differences, we share a lot of common history, and this results in a certain amount of conformity in terms of culture.
Japan, on the other hand, was practically unknown to the West until the 1700s, and only really began to open up to the rest of the world during the 20th Century. It isn't just a different culture to our cultures in the west. It's a culture where practically everything has a completely different historical origin to here in the West. Their architecture is different, being lightweight and easily replaceable due to how many typhoons and earthquakes they experience every year. Their religions are completely different, being utterly devoid of any Abrahamic influence. Their society was, and still is, different to ours in the West. Historically, Japan has had a far more structured hierarchy system than any Western country, and for anyone interested in anthropology, their history makes for an incredibly interesting read. Their language and system of writing is rooted on completely different ideas to our Romanised way of speaking, making use of component pieces to build words almost like lego bricks.
In short, for anyone interested in how culture and society works, Japan makes for an instantly clear contrast to how Western culture has evolved.
2) Japan produces a lot of anime.
Here in the West, we tend to produce cartoons for 2 purposes: comedy, and kid's entertainment. Even acclaimed cartoons like Batman: TAS are still aimed squarely at the under-14 demographic.
There is a demographic of people who want to both enjoy animated shows, and experience subject matter that is more adult and mature than what is typically on offer in the West. That's where anime comes in. Even the children's stuff tends to include greater amounts of mature content than Western cartoons: think of all the popular shows like Naruto and Bleach, and how much those shows actually focus on violence and death. And then there are the shows like Akira, Neon Genesis and Cowboy Bebop, which are not really aimed at kids at all, and are instead adult stories told through the medium of animation.
If Western companies produced more mature, story-focused cartoons, we'd probably see a swing away from anime. As it is, Western companies instead focus on the likes of Family Guy and South Park, opting to refrain from making cerebral shows about weighty subjects. For people who enjoy seeing animation, this makes Japanese anime a no-brainer for seeing more serious subject matter told through the medium.
3) Japan is a key player in videogames.
Quite simply, there was a period where Japan owned the videogame industry. During the 90s, every major console was developed by a Japanese company: Nintendo, Sega, or Sony. It wasn't until Microsoft released the Xbox that a western company stepped back in to make their own console.
This means that some of the most popular videogame franchises of all time are Japanese games that were released in America/Europe and managed to find fame. Mario, Final Fantasy, Sonic, Zelda, etc etc. There are successive generations of gamers who grew up playing Japanese-developed games on Japanese-produced consoles. Therefore, it shouldn't be surprising that a lot of these gamers are interested in the country that shaped the way they experienced gaming.
