Remember how Lupin says Harry’s instincts are good and nearly always right? Why are you mistrusting him at this late juncture? In fact, Harry gains infinitely more by choosing Ginevra Weasley over Hermione Granger.
Ginny brings with her the bright, abundant dowry of the things he always wanted in life and never had. He gains a wide wizarding family, full of people he already admires and loves—and even the requisite family priss-pot, somebody about whom everybody else can complain. What does Hermione offer in the way of family? A pair of nice … dentists. A future that means a tiny nuclear group. In the expansive Weasley clan, Harry will be an uncle many times over as well as a father. There, he has a second pair of parents who already care about him. He has big brothers. He possesses a resonant history with them all, and he is attached to the memory of their dead. We can even say that Harry becomes a kind of fraternal twin to make up for the dead Weasley twin, Fred, for he and Ron are the same age and share boyish passion for broomsticks and quidditch. His best friend becomes his brother.
Now then, what about Hermione, his other best friend? (Let’s note here that the books press onward toward the restoration of Harry’s broken world, and that Hermione and others help in that restoration. If you accept that idea, you accept that the thrust of story is not about Hermione—it’s not even about romance or who ends up with whom.) In the context of a Harry-Ginny union, having Hermione marry Ron becomes an added bonus for Harry—she too becomes his family when she marries Ron and becomes his sister. In this way, Harry becomes related to all the living people he loves most. And this is the only way they can all be related, the only way that nobody is left out of the circle of Harry’s deepest loves.
You see? Harry takes home all the toys. The cupboard child who was last is now first.
Marly Youmans writes an open letter to J. K. Rowling. Via Wes Hill, who notes that Marly “explains to our beloved author that the marriages at the end of her Harry Potter books are, among other things, about preserving and strengthening the bonds of friendship.” Recalling other loves than romance should be a strategy for the age.