Promoe not pomoe.
SnW contains moe, but it is severely aware of this and reacts to it in a very progressive way. For example, the use of an otome-kei scenario to remove any male presence among the main cast creates the opening for heavy exposition of an assortment of intimacies, such as fanservice. However, instead of gratifying the viewer by engaging them in those visuals, SnW characters are often wrapped in large, unattractive military garb, with the occasional panchira, paisura, or cleavage shot. The very fact otome-kei is used in a war-time setting already clues the viewer into the fact SnW contains friction.
Also, to have the setting take place in what was once a school, SnW again creates opposition for the viewer to actively achieve moe. It's well known that school-life is popular genre among otaku for its ability to convey moe in a familiar and emotional setting. Placing the characters so close to this stage and permanently separating them from it through the use of a tragic war-time narrative creates a heightened opposition that both spurs the viewer to achieve a sense of moe and, at the same time, prevents them.
SnW is aware of moe, contains it, participates in it and elaborates on it but it also contradicts it at many turns.
Rather than being post-moe, the series intentionally develops contradictions to moe. This is done to decrease the self-conscious nature of the viewer and to further their demographic reach. By juxtaposing the characters and narrative action of a typical moe show with a beautifully developed background setting, you accomplish two things:
You provide the moe you know that your target audience craves. You provide the illusion that the show is not moe and thus it is more acceptable to like it.
Audiences like being pandered to, that much is obvious, but they hate being aware of how much they are being pandered too-- so you just hit them with a few contradicting elements so that you can give them all the moe they want with the justification they need.