In Japanese Budo, there are plenty of people that tend to be (or at least aspire to be) "more Japanese than the Japanese" - a position which I find entertaining at times
I remember visiting a dojo in the USA where the (caucasian) teacher seemed to be speaking (almost grunting) pidgin Japanese but with a Scottish accent (I grew up and went to university in Scotland) - his aikido was fine but I did find the scenario a little bizarre!
Be careful about your interpretation here. My own sensei spent 10 years learning aikido in Japan, and when he's on the mat a bunch of Japanese mannerisms and syntax reappear. But it's not put on--that's the context in which he learned aikido, so being on the mat re-creates them. Might be the same for the guy you saw.
Also, there's value in ritual itself, if the activity you're engaged in has any significance at all. We create ritual to express the significance of what we do--even a baseball game has ritual, as the roshi of the Zen monastery I visit used to explain. The ritual of the dojo ties us to the history of aikido and has value in itself--if we don't use the ritual that's given to us, what do we do instead? Invent it?