It could be that there's still a strong attraction to the masculine underneath a strong fear and revulsion to men. They know what they want, but can't deal with the usual packaging.
And on the other side it may be a confusion between being and having or wanting to be or wanting to be with a woman. It's the same confusion or blurring of the lines that Jenner feels in regards to women and femininity. He feels in some way so attracted to the womanly that he doesn't know in what way he wants to possess it, by being a woman or by being with a woman.
Manly lesbian / womanly lesbian pairings may not account for a majority of lesbian couples, though. A lot of lesbian couples (like gay male couples now) basically look alike.
FWIW, every time a picture like this gets posted the shock and disapproval are a little weaker, so the effect of posting pictures like this may not be what's intended.
Jenner is perplexing because he clearly likes a lot of, what I would consider, manly things, says he is not attracted to men, etc. I just saw a recent picture of him tearing it up on a dirt bike. Not that women can’t ride dirt bikes or do manly things—but you get my point.