Interesting mentality given the number of dojo around the world teaching aikido to non Japanese. This is what Osensei envisioned, right? That aikido would be spread around the world? He built a "silver bridge" to Hawaii in what....1950 was it? Now 63 years later, you can find an aikido dojo in just about every country on the planet.
Well, while not exactly the same, you do see these sorts of things often in Japanese culture.
Japanese people will be more than happy to spread their language, literature, culture and so forth to other countries, but many will at the same time insist, that to truly understand it, you will have to be Japanese. Even during WWII, you can sort of see this concept: Japan still had the same mentality back there, yet fought a massive war, to try and bring in major parts of Asia in under its rule.
It's somewhat self-contradictory, yes, but in my experience, Japanese culture is largely made up of extremes, and opposites. You can see this in vast areas of Japanese culture. An easy example: the Japanese do not openly talk about sex, and has massive issues with a declining birthrate, yet holds the most active porn industry in the world. Or that prostitution is outlawed, yet brothels ("Soaplands") are scattered visibly and openly in every major city in the country.
Seen through those eyes, it doesn't surprise me that someone could hold the belief that "Aikido is meant to be spread to the world, and bring peace through unity through the art" and at the same time say "You have to be Japanese to truly understand it".
Now, whether the founder intentioned it like that or not, I can't say. But that a student would later say so, doesn't surprise me in the slightest.