Dixie,
On Atomos we use Party Finder, not Duty Finder, to learn fights privately before going into the public Duty Finder. Perhaps that was your mistake?
Also, you said you can read Japanese in a later post but you had to translate what you're referring to in this post. It's no wonder they'd be pissed at you; they probably had J as the only language selected, you (like nearly every other EN player on Elemental) likely had J and E selected. You went into a public party, by your own admission aren't literate enough to fully understand everything they're saying in real time, and the party wiped a couple of times. I'm pretty sure you weren't following what they were saying to do so they kicked you. That's a fair thing. If someone not fluent in English joined one of my parties where I had only E selected, we wiped, talked about strategies yet the non-EN player didn't respond or change how they did things and we wiped again, I'd be inclined to kick them too.
I've never encountered this before in my eight and a half years playing on Atomos, but then again, I don't go into anything except Roulettes with J, D, or F selected, only E. It's a matter of politeness and making sure I'm in a group with people who I can communicate with.
On the topic of "xenophobia" and Japanese in this game. Even though they study English from a young age in school there, they really only do reading, writing, and some basic speaking. Their conceptual knowledge of the language coming out of high school is good if they're reading a book at their own pace. 90+% of them aren't fluent enough to be able to read, let alone type, English at Game Speed. For all intents and purposes the great majority of Japanese are illiterate in English given the speed of communication and typing in the game. It only stands to reason that they'd want to play with other JP-fluent people so they can communicate. Selecting J and E on JP DCs helps the EN players get parties, yes, but it also runs the risk of being put into parties that are listed as J only.
It's not xenophobia or racism, it's simply a matter of wanting to be able to communicate with the other players in your party; ESPECIALLY when learning fights, as DixieBell stated she was doing.
To the racism thing. Yes, some individual Japanese, and certain aspects of their culture, are racist. I've lived there and encountered it myself. It just happens to be a very soft and polite thing and not the violent and brazen stuff we see in the West. That being said, I've encountered more racism here in the US than I ever did in Japan, and I'm an educated white guy.