I personally think Janeway did the right thing, and I totally agree with Guy's numbers thing here. But the best reasoning I have heard (and I believe it was from Christopher Bennett) was that Janeway had to save Tuvok and Neelix because to sacrifice them for Tuvix would have been a betrayal to the rest of the crew. They had to feel that her loyalty was to them and not someone that was a transporter accident. Would you have gone on an away mission for her if you knew in the back of your mind that she might not choose you? It wasn't only a choice to save two friends, it was a choice to keep her crew's loyalty. To any effective captain, the crew's safety has to come first, before right and wrong even.
Well that's racism at work there.
(British joke approaching, apologies to ignorant dirty foreigners.)
"This is a Local Ship for Local people."
(But I only care to entertain saavy British people who understand real humour.)
The nature of Starfleet as I understood it was to help "people" who are in trouble.
(Although the Prime Directive does insist that all the little aboriginal races on the fringe have to grow up and learn how to look after themselves before Starfleet will abide to give them a hand which by then they don't really need any more.)
But in Dreadnought, Janeway risked the ship to save strangers who knew for a fact that she was an asshole, albeit to save a planet from a Cardassian bomb B'Elanna launched....And in The Cloud they drained the the ships resources almost completely to feed a giant space baby they'd accidentally raped with their starship, which put them at wits end for probably weeks.
The Captain decides who lives and dies.
B'Elanna had a hissy fit about this very issue in the pilot.
The philosophy of self improvement (through sacrifice) to et all improve the species, and therefore by extension the entire Federation, makes your average human as dogooding as (not being sarcastic) a Mormon on pilgrimage rebuilding a ravaged third world country (When they come to New Zealand, it gets my nose right out of joint, we are clearly 2nd world and doing fine.) because it's a selfless expedition to help out the doomed... Earth was probably self doomed when they started paying it forward in the 22nd century after the Vulcans convinced them that money was stupid.
Yes, but my point, as they said in Star Trek VI: Every sentient person has inalienable human rights, no matter how racist and patronizing that sounds to alien ears.
It is the duty of every Starfleet officer to put their life on the line to guarantee the precision of the mission whatever that may be, not because there will be a value in their death, but because they took an oath, and unfortunately it's a certainly that routinely often some lives, goldshirts, will be wantonly wasted frivolously but it's not their job to wonder how righteous their death is going to be when they suit up in the morning.
It's Kathryn Janeways.