Wasn't Sim a complexly different genus and species?
He wasn't even humanoid, he was a bug mimicing a human.
Sim was genetically identical to Trip and had his personality and memories. Once the creature was injected with Tripp's DNA it became an identical clone. My point was that Sim didn't want to die but was forced into it.
Big differences to me are that Sim was created with the sole intent of saving the life of his originator, Sim had only a few days to live anyways, and that Trip wasnt dead yet.
However, as a sentient being and someone who never swore an oath to Starfleet, Sim should have had the right to choose for himself. Also, Archer should never have authorized the procedure in my opinion.