The reason for this is if we say we're only going to write the "truth" about some topic, that doesn't do us a damn bit of good of figuring out what to write, because I don't agree with you about what's the truth.
La razón es que si decimos que solo escribiremos la verdad sobre un tema, eso no nos ayuda a la hora de decidir qué escribir, porque no estoy de acuerdo contigo en qué es la verdad.