You weren't the only one who was surprised. The studio behind Evangelion totally was, too.
With a new Evangelion movie right around, the corner, the appearance of a plugsuit at a fashion show seemed like clever PR—especially, because the outfit wasn't Eva-esque, but rather, a direct copy.
Japanese anime studios are, as a rule, very protective of their copyright. Gainax, the studio behind Evangelion, is no exception. And with Victoria's Secret being a big company with lawyers and stuff, surely, it contacted Gainax and got permission to use the outfit and not just completely rip off Evangelion. Right? Um...
Gainax told Japanese site J-Cast that Victoria's Secret never contacted them about the outfit, and the studio only learned about it from the internet. J-Cast cited the Kotaku story (even translating some of your comments!) and reported that the studio seemed "perplexed" by the outfit.
No word on what action Gainax is planning—whether that will be legal or just sending a few Eva mecha over to Victoria's Secret HQ.