This sounds a lot like what Tarz told me.

[ She had revisited those memories, using her pensieve. She recites it now, her voice not wavering. ]

'All the worlds that have been lost, they can be reborn again should the Seelie have their victory. All the millions of lives lost will not have been in vain; for life will come again after us. We will have fought to preserve the future's worlds, and all the families that may grow in them, their friendships, all in hope that they may have peace.'

[ Closing her eyes, Hermione breathes out. ]

Do you really think we're doing the right thing?