And he wasn't just a combination of those 2 characters, he became a character of his own, made his own experiences.
Which is exactly how Trill joining works
. If you think that a joined Trill is two distinct personalities sharing a body, then you're astonishingly wrong, and I have to wonder if you even watched DS9. The two minds in a Trill joining become one inseparable whole. There was no more distinction between the Jadzia part and the Dax part of Jadzia Dax than there was between the Tuvok part and the Neelix part of Tuvix. They only became distinct again when they were separated.
Christopher, I'd rather say you didn't understand what I meant. And rather than accusing someone of not knowing even the basics of what they're talking about you should probably start by giving people the benefit of the doubt and ask for clarification. Not everyone here is a native English speaker after all and/or has a similar succinct way of putting their thoughts down, either.
On to the matter at hand:
If you say Tuvix was similar to a joined Trill... shouldn't that also imply that Tuvix should hold the same regard as a joined Trill? That no matter how he came to be this new and now joined life is just as precious as the two individuals he came from?
Biologically, Jadzia and the symbiont never ceased to exist - they were still 2 different entities, not a new 3rd entity. The joining doesn't change one's personality, it just influences it, it gives experience and a new perspective on things due to the collected experience of prior hosts - and that perhaps appears as though it changes the host's (not joined Trill's) personality. IMO you could see that quite well with Ezri.
Not so with Tuvix. He was a new person, made up of the DNA of Tuvok and Neelix with both their sets of memories. But that's it. Tuvok and Neelix were just a thought in his mind.