Everyone wants to save Tuvix because they like him. But nobody wants to save Tuvok or Neelix. They didn't consent to dying so Tuvix could live. If you agree Tuvix is a person, then you cannot disregard that so were Tuvok and Neelix. Where was their funeral? Does Tuvok's family not get it's husband and father back because the crew liked Tuvix better? The two people who's opinion mattered the most couldn't be consulted. If Tuvix is a person, his judgement on the matter is simply too biased as his sense of self preservation would interfere with objective decision-making.