Not liking a genre is different from not liking a .... country and everything that comes from it? I don't see the point of your comparison.
It's that everybody has preconceived biases against specific groups of games that
might follow a pattern, but they're willing to try something that looks to break that pattern. So, for instance, "I don't like racing games, but I love a quick game of Mario Kart now and again." It's not that the person doesn't like racing games, it's that they usually aren't interested in most racing games until a game comes around and proves them otherwise, or grabs their attention. Likewise, "I don't like Japanese games, but I love the Souls series..." It's not that they don't like Japanese games, it's that Japanese games don't generally catch their interest, until one proves that it's worth their time. It can be applied to regions, genres, publishers, developers, or any category of consumer products. I, personally, am usually not into Ubisoft published games... So an Ubi game really has to do something different to grab my attention. I'll snooze through Ubi presentations because I know that most of their games will be Far Cry, The Crew, Tom Clancy, and Far Cry ... and say "Eh, I really just don't like Ubisoft games..." but then maybe at some point something like Trials HD will catch my eye and I'll love it. Still, I'll have that implicit bias against Ubisoft games so I'd still probably say "Eh, I don't really like Ubi games," but I did like Trials -- an Ubi published game.
It's not really that somebody
doesn't like Japanese games or
doesn't like Western games, or doesn't like racing games, or Western RPGs, EA games, it's that they need something specific to their interests to attract them, and a genre of games or the origin of games is no different. And, let's be honest, games from specific regions, games in specific genres, games from specific publishers
tend to share things in common and that makes sense that they do... It's the same thing with almost every other consumer industry.
It's not absurd that someone would develop their own bias for or against a category of products that they're spending
their own money on or spending
their own time playing. It happens with every industry. A lot of people have a bias against American cars as being unreliable, or against German cars for being expensive to repair, or against Japanese cars for using cheap materials or shoddy crafstmanship. These had a basis in reality at some point, but the biases still persist even if other manufacturers from those regions have bucked the trend. It
is absurd for somebody to say something like "
You shouldn't spend your money on Japanese games," but not, "I don't want to spend my money on Japanese games." It's a consumer market, bias is normal, and it's normal to not be interested in something based on previous perception and need something unique and extra to make you buck that preconception.