I guarantee you that "Japan is ostensibly pacifist" because the people who live here right now have no interest in war. The only signals of war and conflict here are American.
No normal people in Japan are interested in the territorial conflicts with China, or constitutional debates about self-defense, or where to stage American military hardware, except that they would like all of that nonsense to end so that they can get on with their lives.
Your 'Pax Americana' is doublespeak on the highest order, as Americans go around the world setting and lighting their own powder kegs.
Yesterday, a V-22 Osprey flew low over my house, and while it is a marvelous sight on many levels it is ultimately the only emblem of death and destruction on a landscape of almost unimaginable serenity. My neighborhood is all bamboo swaying in the wind, old people on bicycles running errands, kids playing baseball and catching beetles, some lazy cats and a lazy river...and here comes a fucking V-22 Osprey overhead.
Meanwhile, a Marine in Okinawa is accused of killing a young Japanese girl. These things just simply do not happen very often in Japan, so the attention on this murder is intense. Okinawa is a really nice place, and the people there would prefer not to deal with this cyclone of...death and destruction in their midst. It made sense at one time, but it really is not that time anymore.
I know that you have a hard time overcoming the urge (programming) to see America as the great liberator of the world, policing the wild streets of lesser, unruly regions that would be lost without Uncle Sam, but...at some point, the big bully protecting the block becomes the only problem that anyone on the block is having.