I think you are all forgetting that the Queen wants her. She said so in her letter to Ciel.
Also, you seem to forget that every chapter ending is either bittersweet or tragic.
Huh, annoying button? I'm sorry I'm using the old version, much more comfortable for me to use than the new (I don't like it), so I don't know about that feature. But if you did click it by accident, that's okay, accidents happen. At least you warned about it, and apologized for it. (I don't think many do that.)
(Personally, if they do have it, I guessing it gets abused a lot.)
I am under the impression that Ciel might end up with either one or two more strays in his house after this -hint hints at the green witch and her butler-