Exactly. It's really very simple: Tuvok and Neelix are dead and are never coming back. Tuvix is a sentient being, with equal claim to the rights the Federation recognizes and guarantees for all sentient beings -- including the right to live. Tuvix can be killed, but Tuvok and Neelix cannot be resurrected, only copied. So the choice is between respecting an innocent man's right to live, or killing him in order to create two new people who remind us of people who are already dead. I've never been a parent, but I gotta say, I don't think I would kill an innocent man just to create a new copy of an already-dead son or daughter. ETA: Once again, this argument has already been refuted. A properly-functioning transporter ensures continuity of consciousness -- the same person steps off the transporter pad who stepped onto it, and was merely transformed into still-conscious energy temporarily. Tuvok and Neelix did not experience continuity of consciousness -- their consciousnesses were ended and a new one created.