the other is still made of people who deserve to live their own lives.

But those "people" (i.e., the clones of Tuvok and Neelix) never existed in the first place.

The main issue in this episode is that two sentient beings were effectively destroyed against their will to create a new sentient being. To rectify the issue of two sentient beings being destroyed to create one new sentient being, the one was destroyed against his will.

But a clone of Tuvix would not come into existence at the expense of any sentient beings besides the original Neelix and Tuvok. It doesn't solve the original "we're killing a sentient being to bring back our friends" problem the original Tuvix caused, but it doesn't create new problems either.

We could just transporter-clone and combine Tuvok and Neelix into Tuvix in one shot. The net effect is one new being, Tuvix, at the expense of nobody. Doing it by cloning Tuvix is just an added intermediate step.