Repulsive as it can be, this very recalcitrance has served Enharza well enough on occasion. Driving the Overkingdom off through sheer, arrogant decadence rather than the force of arms is no small feat, after all. Kirsch remarks almost parenthetically, mostly just to make his presence in the room palpable. He would really rather not deal with Emalia (what could Sinna see in her, really?), let alone Orbal, but the last thing he needs is to become unwelcome sooner than he'd like, so putting up with the two of them is likely his best bet for now. Besides, Meagan and Clytemnestra are way closer to the Lady than he ever was; should they be dishonest with him, they can always take advantage of that, especially unless he plays nice.
Subsequently, when he finds himself listening to the Duke's toast ringing through the room with an unwanted drink in his hand, he is quick to raise his glass as well, adding a sly Long may she reign! before taking a symbolic sip of his wine.