If you buy the transphobia canard, there is no such thing as 'essentially female". And that's the point.
Depends; some of the Trans folks seem to at least "believe" they should have been or are some kind of very subtle hermaphrodite.
But it doesn't lend itself to supporting that argument I suppose.
On the other hand; some feminist or SJW types seem to think of Gender as something you "identify" as and yeah at that point, there wouldn't be anything as "essentially female" or really any real point in claiming it.
Be about the same as having a major part of your identity be "I like the color pink and fluffy things....."
Doesn't seem like a real big deal to go on about and protest.
But if I had to guess, would say mainly people with some kind of disorder and/or a severe need for attention.