It would not be right for a brother Christian who believes there was one in their mist who has Biblical error to not point that out. It would be the same thing as seeing a fallen person along side of the road and just passes them by without offering help. Even if that person was not looking for help. What good are we if we just let things slide by? Do we think God will over look our inactions to let that person continue along their way without giving them what they needed? If we really pulled off the blanket completely and exposed all of the Catholic beliefs system you would for sure have a very hard time defending it here.