It's a bullshit hypothetical when there are solutions that don't require murdering anyone.

It's not meant as a parallel of the episode. But "the ends justify the means" and "the needs of the many" would say that organ harvesting is perfectly fine as well. Which was what I was responding to originally. And while there are options (voluntary organ donations and taking from the dead) there's simply not enough organs to go around. People wait on organ donor lists for years, some of them die while waiting for an organ that would save their life. This would solve that problem.

Has every alternative been tried and killing random people is the only way ro save others as a last resort?

Had every alternative been tried with Tuvix? That answer is no. Janeway never even considered trying anything else. We know that because the subject of Thomas Riker never came up. We know the transporter is capable of duplicating people exactly. There's no reason given as to why they didn't even try to duplicate Tuvix and split one of them apart.

That's my problem with this. What Janeway did was morally wrong, you can see it in her face at the end when she kills him. She knows that. But sometimes the morally wrong thing is the necessary thing to do. I agree that it's wrong but in that situation, I'd have done the same thing. If it was necessary after researching alternatives.

There was no reason that they had to separate them right then. The writers could have made it so that it needed to be done immediately. Make it so that it needed to be done now, waiting any longer could have made the process irreversible or more risky to Tuvok and Neelix. That way a decision needed to be made quickly, no chance to do any research.

Or that when they researched it the only thing that they could find was Thomas Riker, but that the odds of success are practically zero. That what created Thomas Riker was a "miracle" that would never happen again. And that attempting it would not only be likely to fail, but kill Tuvix in the process. So now there's three options, Tuvix lives or Tuvok and Neelix live or we risk all three lives on an extreme long shot. And I doubt anyone would think the third option was the best choice, leading back to the original moral dilemma. Or just have a simple "we've checked and couldn't find any alternatives." Ok, they suck at research but at least they tried to find some way of saving all three.

The problem I have with this is that it wasn't a neat morality problem that the writers wanted it to be. But it could have been with a very minor change. IMO, the way this situation is presented Janeway was wrong. Not in what she did exactly, but in what she didn't do. If the writers had said that they looked for other options and found none and she made that decision, I'd agree that it was the correct decision (but still not the moral one :P )

Which is why I like the one with Archer better. He was under a time constraint. Which made a snap decision much more appropriate. He didn't have time to find other options. It was "do it or Earth dies." And while his decision was unethical, I also think that was necessary and the right choice.