perhaps a legacy of Prussian influence over meiji era education and social reform than anything strictly war related (though obviously that they were part of the war I bet influences a lot of counter-cultural otaku subculture)
war/battleship/tank otaku etc fascinate me because I feel like a lot of the military/gun otaku that I see represented are almost apolitical generally speaking. of course being apolitical is itself a political decision but there seems to be a lot less overt ultranationlists who are also military otaku. people who are, like, tank otaku or hwatever are like... purists. it's all about being the best technical specs or performance or being good at being a tank, and never about the aims behind actually having a tank
of course i say this as someone who can't easily read japanese forum threads, so what do i know