[Strike Witch]

I get where you're coming from, but it's got more to do with the Japanese view of their own language, because they generally consider that copulate thing to be a bit semantical when it comes to the guts of the sentence. An average Japanese girl dressing up can look in the mirror and say "I cute" and get away with it, because it's not considered that important. You get it in reverse sometimes when Japanese will ditch words like "to" and "be" and so forth from their sentences because they're assuming it's like Japanese and not that important.

Hell, a situation where someone would be using desu in a sentence probably wouldn't have kawaii in it, unless the person is psychotically polite.