The statue is also undoubtedly an icon for both Rio de Janiero and Brazil as a whole.
So is the Amazon or Igacu Falls. So it comes back, essentially, to "Which would win a popularity contest?" which I think is a poor basis for choosing Wonders (okay, the other two aren't artefacts, but I think Igacu should be a Natural Wonder).
Also, there are almost 200 countries on Earth - why should Brazil be singled out to get one of its national symbols included as a Wonder just because it's a national symbol of Brazil, if it wouldn't otherwise be worthy of inclusion? The stars and stripes is a national symbol of the USA, and is an artefact, but I wouldn't say the American flag should be a wonder either.
Indeed,Christo Redentor reflects the big influence of the Christianism over brazilian's culture
But that is nothing unique to Brazil, it's not a feature that distinguishes it from neighbouring countries or from much of the rest of the world, and at least in the international consciousness it's not seen as a sufficiently stereotypical feature of Brazil that when people think of Brazilians their first thought is of particularly pious Christians. The Statue of Liberty represents "the Land of the Free", Cristo Redentor can't really be said to represent "The Land of the Christian" - Brazil has no particularly unique claim to that.
By the way,what's wrong with Christo Redentor to justifiy the replacement for another wonder(and since when a world wonder is replaced?)?
Well, all the reasons I've already given as to why the statue doesn't really meet any of the criteria to qualify as a Wonder.
The New Seven Wonders poll was conducted a few years ago, originally under the auspices of UNESCO, to select seven Wonders to reflect the greatest achievements of the world as now (rather than classically) recognised, excluding the "original" seven. Originally experts shortlisted various proposed sites - about 20 or so - but UNESCO distanced itself from the project after the final selection was opened to popular vote; I believe the original intent was that it should have been a wholly expert-led process. The final seven sites were:
The Temple of Kukulcan, Chichen Itza, Mexico
Cristo Redentor, Rio de Janeiro, Brazil
The Great Wall of China
Macchu Picchu, Peru
Petra, Jordan
The Taj Mahal, Agra, India
The Colosseum, Rome, Italy
Admittedly, I don't have any evidence that the selection of Cristo Redentor over, say, Angkor played any part in UNESCO's decision, but it is notable that only one of the above seven sites is not part of a UNESCO World Heritage Site. Guess which one that would be.