Scanned through this thread quickly, and it is disturbing. Likely the people in charge could not tell a muzzle loader from a machine gun. And they are sensitive to some peoples' antipathy towards any firearm. That said, the issue of liability is unmentioned, but it is an elephant in the room.
We live in a litigious nation. We mint more new lawyers every year than there are practicing lawyers in Japan. Should some bystander be accidentally shot at one of these events there would be a sh**storm in the local media, multiple lawsuits, and ended careers. The kind of prospect that would make a "public servant" bury his head in the sand and deny you.
Around here, horse farms now post signs about the "dangers" of being around horses. Surprised the local gun club has not done something similar.
I do think that a club may well be willing to host your event.