The Word for World is Forest (Hainish Cycle, #5)

by Ursula K. Le Guin

“You’re children,” Gosse said with hatred. “Children, savages. You have no conception of reality. This is no dream, this is real! You killed Lyubov. He’s dead. You killed the women—the women—you burned them alive, slaughtered them like animals!” “Should we have let them live?” said Selver with vehemence equal to Gosse’s, but softly, his voice singing a little. “To breed like insects in the carcass of the World? To overrun us? We killed them to sterilize you. I know what a realist is, Mr. Gosse. Lyubov and I have talked about these words. A realist is a man who knows both the world and his own dreams. You’re not sane: there’s not one man in a thousand of you who knows how to dream. Not even Lyubov and he was the best among you. You sleep, you wake and forget your dreams, you sleep again and wake again, and so you spend your whole lives, and you think that is being, life, reality! You are not children, you are grown men, but insane. And that’s why we had to kill you, before you drove us mad. Now go back and talk about reality with the other insane men. Talk long, and well!” The guards opened the gate, threatening the crowding yumens inside with their spears; Gosse re-entered the compound, his big shoulders hunched as if against the rain.

Hm