Seeing Anya (the girl pointing at pictures), I'd guess the author is partial to Japanese culture. As their writing system does not have a concept of upper/lower case, he might just have determined that they are superfluous. Or he is simply an eccentric. Though I guess this is one of the things that some folks will not care and others getting hung up mightily.

I personally don't really mind that bit of capitalization that English does. German is much worse.