What if you want to write the name of an ESL speaker, who might well come from a country where names often don't only consist of ASCII characters? Or do they tell you to knock that off too?
Don't get me wrong, I'm not defending this "ASCII is good enough" mentality. But in the sort of environment where management is telling people not to write words like 'naïve', it's likely that somebody named Jìng is going by 'Jing' or 'John' in the office, if for no other reason than because their boss can't be bothered to figure out how to type ì without copy-pasting it. This has been my experience anyway. This sort of corporate international accessibility seems to expect concessions from everybody.