Because people pray and then feel like they have done something, when in reality they have done nothing and the people they are praying for are still in the same position.
If they recognized their prayers did nothing, then maybe they would actually do something that created some tangible change for the people down there.
But that is what you don't seem to understand, people of faith (most) trully believe that prayer helps just as much as money and other means and methods of "helping". As a non believer you don't, and that is your right and opinion. But don't trample on people who believe that it does help. Praying for miracles, like I want everyone in the Haiti to be fed and their houses back together tomorrow, is ridiculous. And I agree, that if you judge prayer working on those ridiculous "prayers" then yes, you have a point. But saying a prayer for the country and to be with the people in Haiti as they recover through this mess, or God to be with those making the decisions that effect Haitians, I don't believe is a waste of time.
Show me empirical evidence that prayer works, and ill retract my statement.
BTW, my father is a "man of faith", and even he knows that praying doesn't do shit.
I can't show you personally. But yes, in my life is has worked. I would explain but I'd rather explain calculus to my 4 year old, because he might actually listen.
I don't know your father but I guess now I understand a little why you doubt God and people of faith so much.