What is wrong about the concept of life on other planets?

Are we alone in the Universe? Many scientists believe that the answer to this question is no but we are yet to see concrete evidence about “aliens from other worlds”. Many ufologists would mention Roswell and several different conspiracy theories claiming that there are many proofs that we aren't alone in the universe. But we are still waiting for definite yes from the mainstream science.

The latest interesting news related to this topic comes from the University of New Mexico scientists who have studied two Martian meteorites that originate from the interior of Mars. 

By analyzing the water content in these meteorites the scientists have concluded that that the amount of water in places of the Martian mantle is much bigger than previously  estimated and is in fact similar to that of Earth's leading to conclusion that Mars could have sustained life.

Don't get me wrong ,there is nothing wrong with this conclusion. Mars could have indeed had plenty of water in the past. And yes, this could have result in life on Mars so the conclusion is definitely right but the concept needs some expanding, on my opinion that is.

I for one, do not agree that water and oxygen are necessary ingredients to support life in entire universe, life like ours yes, but general life no. Given our highly limited knowledge about the Universe and our own existence, I believe that it is totally wrong to start with the assumption that water and oxygen are necessary substances for life to develop on other planets.

We can judge the life from the extremely limited perspective given the vastness of our universe so we should definitely expand our current concept of life on other planets.

Who gives us the right to categorically refuse the possibility of life on other planets just because there is no water or oxygen? Who knows what kind of strange and unknown elements and liquids exist in Universe, substances that will perhaps be discovered by our future generations giving completely new light on the definition of life itself?

Our current hunger for knowledge is positive thing, something that moves our civilization forward through technological and scientific innovations. However, in order to fully embrace this growth in knowledge we need to keep all our concepts open, especially the most important one, the concept of life.