By that logic Tuvok and Neelix didn't actually die... there was no corpse. The fact that he was an accident doesn't matter. He was alive and a living sentient being regardless of how he came to be. If he was born, if he was cloned, if he was a transporter accident, it doesn't matter. He's alive. There is no moral way you can defend the murder of one person for the benefit of the group. That was the argument used for slavery. That the subservience of a minority race benefits the majority. As for the creepy comment... what's it matter? You think a guy who looks creepy deserves to be murdered?