Eighty-Six is not a grand story about standing up against oppression or uprooting the system. It is not trying to tell us anything substantial about racism or war aside from things we as humans should already know.
Eighty-Six is much simpler, it's a story of children making the best of their fucked up situation, and how these children react once they are finally given an out. Racism and war are merely tools, the setting, to a boy-meets-girl story.
The series rides on the struggle of these two characters, the boy who only knew of the battlefield and the girl constantly yearning to be by his side. All I can say is their struggle touched me, as frustrating as the both of them were at times. But hey, they're teens, they're supposed to be frustrating, especially since neither seems to be fully right in the head.
Shin is not someone who wants to be off the battlefield, and Lena is not someone who wants to be left behind as others fight on her behalf. These two deserve a peaceful life after what the world has put them through, but their pride and idealism won't allow it. The series' main struggle is these two characters finding meaning in each other, and by extension, finding meaning in a world without combat.
Once the series nailed the MCs, the rest is merely icing on the cake to me. The world is interesting enough, far more than other Light Novels care to build nowadays. You don't really reed LNs for their prose, but the translation is great and often doesn't actually feel like an LN. My only gripe with the series would be its criminally underdeveloped side cast, especially since I like them already and want to know more.
10/10 would cry to Theo's rant again.