It's Perfectly Comprehensible to me

According to this admittedly not-very-scientific mapping from Strange Maps (a really interesting site, by the way), the speakers a lot of languages express bewilderment at something by saying that it is Chinese to them, but the only analogous constructions in Chinese involve things like 天书 and 鬼符。
Is that indicative of superior understanding of other civilisations and their languages on the part of the Chinese? Or just a sign of pride and conceit---we believe no foreign language is beneath our understanding, even though we might not actually understand any? Or is it a result of China's past relative isolation from further parts of the world? Such isolation could have meant that while the few foreign tongues nearby were readily understood, the further ones, which might not have been comprehended so easily, were too distant and rarely encountered to find their way into such expressions of bewilderment.