Contrary to popular belief elsewhere in the world, most Japanese are well aware of existence of "comfort woman" and "Rape of Nankin". People are well aware of Pearl Harbor, too. How can they not be.... it's talked about in detail everywhere including in Japan.
I had a benefit of studying world history from two completely different view points: that of Japanese and that of American. While this was only in high school, the treatment of the same event is quite different. If I didn't know any better, I'd believe we are talking about two different events.
In Japan, there is a concept of not exposing dirty fact to outside while acknowledging internally or privately. It is often called "gaiken" - literally translating view from outside. People mount a protest when this gaiken is tarnished. It takes decades, or even longer, for these facts to become so common place that people are able to discuss it in public.
I believe this is what is happening. Myself being a Japanese decent, I will withhold my judgement on this practice of gaiken but that is the culture behind it.
This is changing in today's younger crowd. However, Nikon is an old company largely run by older generations. They got themselves in a jam where either way they move, they face fierce criticism. They cancelled it. I'm not sure if I blame them. It's a company after making profit. They are very unlikely to take unpopular position and go against majority - especially those who drive the economy and thus the company.