Life On Other Planets

I don't understand why outer space experts and scientists think that presence of water is the only indicator of life anywhere in the universe. It is true that life on earth is mainly due to the presence of water but I don't think water is the only pre-requisite for life.

And by the way, what is LIFE?

Our definition of life is based solely upon our understanding of Life. In other words, we are very biased. 

What if there is Life everywhere but we just dont have the ability or capability to detect it? What if there is life on Mars that doesn't need water for existence? What if Mars inhabitants consider water to be the deadliest poison and are trying their best to get rid of it? 

I think we should stop spending millions and billions on space exploration as it not really going to solve any of the problem we are facing here at home.

Spending so much just to find water on planet X and to find out if it is inhabitable or was inhabitable in the past, is just BS!

Lets take care of the people on this planet who "really exist" and "really need water" but are dying just because they don't have to clean water supplies.

I think space agencies should be turned into water purification companies to bring bottled water prices down by creating more competition.