I so speculate, because Butcher routinely says the White Court can pass as human under mist circumstances. What if the Jade Court is one more subversive level beyond that? It does make for a great survival trait. And if they were into cultural manipulation, rather than individual, they could feed off the zieghtgeist of whatever they proffered. Ancient Mai might have the White Council in thrall, albeit unknowingly, manipulating the whole society rather than particular members. If so, she certainly would regard any Black Council as a direct competitor. What if Peabody had been working for her crew, for instance? Multiple black interests add intrigue and I wouldn't put it past Butcher.
That would certainly make sense - the Black Court are pretty noticeable, looking like reanimated corpses and such. The Red court are somewhat noticeable, given the right circumstances where their meatsuit gets a bit skew-whiff. The White Court could pass for human quite easily. We haven't heard anything really about the Jade Court, so they're either quite niche, or just *really* good at hiding.