Because Mario isn't particularly 'japanese' in the first place?
4G: This interview has taken a sudden turn. Why did you decide to quit? Your statements have been provocative, but you've always spoken as someone from Capcom, wanting to change the company.
KI: Yeah, I want to work at Capcom. But, how should I say... Circumstances are such that I can't work there anymore.
4G: I can easily imagine that there might've been issues with your statements or projects, but were there really such big problems?
KI: What should I say... I'd probably say that Capcom's path as a company has changed. Though my leaving just comes as a result. It might get pretty long, but do you mind if I explain?
4G: A bit ago, you said, "I tried the same thing from within Capcom." Were you able to effect change within Capcom?
KI: If I had, we wouldn't be talking about this today. (laughs)
Certainly sounds like he was ousted.
EDIT: from reading more it seems like a combination of studio pressure and his own desire to leave.