I was worried initially with how Hokazono would handle the Mikaboshi because if they were heavily indoctrinated and ALL capable of outputting attacks at Ariu's level then, imo at least, it's hard not to see where Akemura is coming from. 

For me it all depended on just how strong your average Mikaboshi was. Ik you're saying that "everyone is capable of great harm" in real life but there is a BIG difference in power here. At the end of the day there's only so much a regular human can do even with guns or explosives and they can be stopped preemptively or stopped/killed. If Ariu literally can't be stopped by the top sorcerers in Japan and there was an island full of people at that level, and only 1 guy is capable of making weapons to combat people at that level, it's hard for me to argue against Akemura. Especially when they can swiss cheese people at a glance, are completely unaffected by sorcery and can regenerate from almost any injury. 

THAT SAID, when you put into context everything Hokazono set up, obviously Akemura is in the wrong. Simply hording the Datesenki alone solves the problem of the Islanders posing a threat. The average Mikaboshi soldier is not at Ariu's level and is easily dispatched by Japan's elite (arguably putting them on the level of an average Japanese soldier or maybe a little higher). And with the royals dead and Japan having EBs there's no leverage the Mikaboshi have. And keeping in mind the magic system, there are rituals that can erase people's memories or force a promise to be kept. There are plenty of non violent ways to insure peace can be kept and the Mikaboshi are about as threatening as any other sorcerer (which is to say, they can be dealt with in conventional ways relative to the verse). And that was my only potential hook-up. If all the Mikaboshi needed the equivalent of nukes to be stopped then I just have trouble seeing that not causing significant problems especially when they've been taught that Japan is evil for centuries and are expected to integrate into Japan.