Sartre, in What is Literature?, brings up poetry in this context- people have been asking him why he doesn't publish more poetry in his journal. Sartre says he wants signification, which "throws us into the world," rather than "word-things" that separate us from the world. But Sartre clearly doesn't know enough about poetry, or "the world" in a general sense, to make an intelligent judgment. No one conversant in Keats, especially, would mistake poetry for "choosing to lose."
This is a quote from What is Literature?:
Poetry is a case of the loser winning. And the genuine poet chooses to lose, even if he has to go so far as to die, in order to win...he is the man who engages himself to lose..he is certain of the total defeat of the human enterprise and arranges to fail in his own life in order to bear witness, by his individual defeat, to human defeat in general.
Sartre never explains what exactly he means by "lose": lose in love? Lose money and starve? Lose notoriety and live in obscurity? He makes the fatal, immature mistake of treating art like an Olympic sport, in which winners are crowned with gold metals and losers slunk off into interminable, media-eschewed shadows; and that kind of crass, vulgarized treatment expresses the dark side of twentieth century lit-crit.