I want to live!
- EvilKirk’s last words
Whatever else you want to say about EvilKirk, it’s pretty clear that he didn’t want to be merged back into the single Kirk. Despite this, there is no shortage of reasons why it was a good idea to merge the Kirks: the Enterprise needed its CO back, GoodKirk wanted to do it, and it seems possible that the strain of remaining split would have eventually killed EvilKirk anyways. However, the fact remains that EvilKirk did not consent to the procedure which ended his existence.
Clearly the circumstances here are quite different and there’s basically no argument to be made that allowing EvilKirk to continue to exist would benefit any involved party, EvilKirk included. But for the purposes of this comparison, the only fact that really matters is that EvilKirk was just as passionate about his desire to continue existing as Tuvix was.
Yet—and it’s obvious where I’m going with this—“Spock murdered EvilKirk” is not a meme.
So what gives? Did Spock murder EvilKirk or not? If yes, why does he get a pass while Janeway is condemned?
Technically yes. Although it also helps that it is a TOS episode, which never had quite the same level of popularity or scrutiny as its later shows. It just gets brushed over by the other issues.
The other is that the Kirk separation had more of a justification behind it. Both Kirks could only last so long before the separation killed them both, putting on a time-pressure for them to be reintegrated, before that window was lost.
By comparison, Tuvix didn’t have that time-pressure. He could have been separated at any time, and the procedure to separate him had a relatively small chance of working. Janeway could have separated him then and there, or some years down the track.