All Truth

Joseph F Smith once said the following:

“We believe in all truth, no matter to what subject it may refer. No sect or religious denomination in the world possesses a single principle of truth that we do not accept or that we will reject. We are willing to receive all truth, from whatever source it may come; for truth will stand, truth will endure. No man?¢‚Ǩ‚Ñ¢s faith, no man?¢‚Ǩ‚Ñ¢s religion, no religious organization in all the world, can ever rise above the truth” (Gospel Doctrine, 5th ed. [1939],1).

Is this true? Do Mormons really accept all truth no matter its source? Even if the source is critical of the Church?