Because I value it to be true....

In the comment by Irrational, an important consideration is required as a sieve to ascertain that our observations are not skewed by our bias expectation. The term used is 'confirmation bias'.http://en.wikipedia.org/wiki/Confirmation_bias
From brand loyalty to alternative medicine, many more in between and even exceeding the range, we confirm a lot of our opinion with choice facts, and very often ignoring contrary facts.
One friend of ours boasted that he refused to take certain medicine for his heart condition and chose to take wheat germ to prove the product he was also marketing. Armed with a lot of attractive brochures he would point out the testimonies of remarkable cures. Sadly, this friend of ours had to drop dead due to a heart failure not long later in a social gathering.
How I admire the love of parents on their child, and even more if their child is disabled. Nothing of what we could put on paper, some equations, list of pro and con or a scrap of justification, could explain the love that turned into a duty of care to such child. This child is still loved, even if you would sympathies with their state of affairs.
World views held with the conviction at a personal level should be tested this way. Some objectivity and with critical thinking should be done  in interpreting observations. It may not be easy to step out from our bias, but we should try to. It must be true because it is and not that because we want it to be true.

Thanks Irrational.