> Is anime & JAV to blame here?

Why "blame"? Isn't it perfectly reasonable for people to take more interest in a country that's supplied them with interesting cultural exports than one that hasn't?

> Foreigners who speak Chinese are way more rare than those who speak Japanese, therefore making it a more valuable language to acquire for business, diplomacy and travel.

Only to the extent that you want to do business, diplomacy, or travel with China. More people are interested in Japan.