I don't see how this is offensive. Multiple language menus are nice if you have a very cosmopolitan clientele, but if you don't, why bother? When I was in Japan, the best places with food had Japanese only menus. Either you learn to read it or go someplace else. That's part of capitalism too: you don't have to accept ALL clients. It's your business, run it as you see fit.
I know...should have put a smiley or some dern thing on the end of my post....