Subpar Spatula
Banned
You could write this about most stories. They exist within context, they explore it but their themes are transcendental to the physical location.
GITS has a defined geopolitical situation (less in Shirow's original manga, more in other works), it has established Japan as a superpower, there is an obvious self-congratulation of japanese capacities with technology (the so called Miracle), several episodes are based on Japanese past occurrences, there is a look to the past of japan, the JGSDF and how the country distanced itself from wars, and if the second season of sac serves as an inspiration, the entire plan of Gounda is the return of the Japanese colonial empire. It's very much a Japanese story.
You can't say this about all stories, though. There's a large difference between Akira and Ghost in the Shell because one is actually focused on Japan. Having a story unfold in a country doesn't make it a story about that country. Did Infernal Affairs revolve around Chinese society? Let Me In? Oldboy? What about the inevitable The Raid US remake? These stories are about something more than their locale, and saying it is in a stubborn manner isn't going to convince people.