How do fans in Japan react to Scarlett Johansson playing Motoko Kusanagi in Ghost in the Shell?
While this is a fair question to ask and I don't wish to marginalize the reactions of the very people from whose nation the Ghost in the Shell franchise came from, I'm afraid their answers are being taken the wrong way and used to prop up some of the wrong-minded reasons some people support Scarlet Johansson's casting.
Maybe it's wrong, maybe it's understandable, the fact of the matter is when you mention "American person" to a Japanese person, they will think of a white person. Never mind that there are plenty of non-white ethnicities that comprise the USA's population. This is why when asked what they think of a white person being cast in the lead role in an American adaptation of Ghost in the Shell, their response might understandably be:
Translation: "That's natural, isn't it? / But of course, what else?" Do you really expect the average Japanese person to be cognizant of parochial American social issues such as the plight of marginalized Asian American actors/actresses in Hollywood? Of course not, but as Americans we know better than that.
Therefore it's perfectly natural that a random polling of Japanese people would reveal none of the backlash that has arisen in America. Unfortunately, some people take the lack of negative reaction from Japanese people as proof that this really is "all just a lot of to-do about nothing at all".