It might not be Vitalik who did it...but it very well could have been an insider who felt it was necessary.  This is the power of crypto.  

In the world before it, you were forced to choose.  Instead now ETH holders get equal stake in both chains and see which one is considered most valuable.  Some will sell ETH and buy into ETC, some will sell ETC and buy into ETH...others exit completely and still others will hold both tokens.   Consensus will be found in the long run and eth original eth holders benefit from the competition between the two.  

To me...this is the most brilliant move I have seen come from ETH yet.