In this case, she's taking on the inconveniently-still-on-the-books Roman Catholic claim to be the One True Church of Christ. In all fairness, she frequently pokes fun at those Protestants she calls "The Truly Reformed."
In other words, she's a traditional Anglican, allowing for a breadth of Christian expression while noting that some expressions cannot be binding upon the whole church. On to the fun:
It is either the Truth or not the Truth. If I am indeed Queen Cleopatra, than my behavior—my insistence that all bow when they enter my room, my expectation of men falling at my feet, my wondering where my royal mahogany and silver-engraved chair is, my claim of the title Last Pharaoh of Egypt, my demand that my image be stamped on gold coins, other people’s mention of my wit, charm and “sweetness in the tones of her voice” and so on and so forth are perfectly reasonable and acceptable. If the breathtaking claim is actual reality, then many things become clear and reasonable.
If it is true that I am Cleopatra, men of power should gravitate towards me like flies to honey.
On the other hand . . .
If I am not Queen Cleopatra, then not only are my pretensions unreasonable and foolish, but men should flee as hard and as fast as their legs can carry them from me, as I am in the grip of a serious delusion and fantasy that makes me mentally ill and highly dangerous to others’ happiness and well-being.
Sadly, our own Episcopal Church has positioned itself as a One True Church, coupling claims of unique spiritual revelation with once-rejected-now-asserted claims of bureaucratic "hierarchy." We've united the worst of Upper and Lower Egypt, Red and White Nile. But at least Presiding Bishops will have some memorably cool tombs in the future.