1) In my opinion, learning cultural sensitivity is a noble goal, no matter the reason. At least you made the effort to learn the manners and societal norms. Better than some gaikokujin I've met in Japan (I've got some stories, if anyone wants to hear them).

2) Gaijin is becoming a more and more commonly used word in Japan and Japanese studies, I've noticed. A case of Slang becoming part of the regular speech.

3) I read in a magazine article a couple of years ago that one of the reasons that Japan is facing population problems is beacuse of intercultural relationships. Something to ponder.

Some other opinions of mine:

I've been studying Japanese for 4 years now. I started because a) Pop cultural fads (AKA: I liked anime and manga) b) my friends were all doing it, and c) an interest in the Culture. In short,I started learning Japanese due to the same influences that most young people learn it. And now, I've come to a conclusion: who cares why you started learning Japanese/language of choice? You're still making the effort to learn about something that is outside your comfort zone. And in the process, you might start to look at things differently.

My 2 cents.

P.S. There are a couple of very good books on the surging interest in Japan that I highly reccommend:

1) "Japanamerica" by Roland Kelts ( Link:http://www.japanamericabook.com/ )

2) "36 Views of Mt. Fuji: On Finding Myself in Japan" by Cathy Davidson ( Link:http://www.amazon.com/36-Views-Mount-Fuji-Finding/dp/0452272408 )