I always liked this word. It follows the morphological pattern of sacacorchos or aguafiestas: third-person singular verb + plural noun. Someone "who spares your life" or allows you to live is a bully, or someone who acts like they are braver than they are.
"Perdonarle la vida a alguien," to spare someone's life, means to condescend to them. So if someone writers that in a newspaper column, someone spares Borges's life, it means they are treating them with condescension, deciding whether Borges can live or die. It is arrogance, or the arrogation of an authority the critic doesn't have.