Trueborn have a 2+ BS, and "When making ranged attacks, Ignore any or all Hit Roll and Ballistic Skill modifiers".
To answer your question, Consummate Swordsman isn't affected by it because that rule only applies to melee attacks. So Melee Hit Rolls of 1-3 indeed always fail.
Hypothetically, if there was a rule like Consummate Swordsman, but for ranged attacks, I think that would count as a Hit Roll modifier, meaning the "Ranged Consummate Swordsman" rule would be ignored, but I'm not sure. Either way, I don't think there is such a rule, so it doesn't matter.
In short:
Trueborn hit ranged attacks on 2+. Always.
Units with Consummate Swordsman can never be hit in melee with an unmodified roll of 1-3.