Why anyone who tries to tell you that "life's not fair" is talking a load of rubbish at you...

We often hear the old maxim "life's not fair" splurted out at us, often after we have plead a case where an injustice has been done upon us, and hope for some compensation or sympathy from the person who then goes on to use the aforementioned phrase - all with the basic message of:
"If anything, it's more YOUR fault for not realising something that is a worldwide occurrence than it is MY fault for not doing anything to solve the problem."
We're all familiar with the disappointed, downtrodden feeling we then feel immediately after, betrayed almost by someone we thought we could rely on.
The truth is (I believe) that actually, on a mathematical level life SHOULD be fair. If we theorise that the first generation of the human race were a bunch of individuals all of whom had a more or less equal chance / opportunity to excel, then that would lead us to conclude that it is the nature of human beings that is not fair. If when we say "life", we refer not only to all living organisms on earth but to the experiences of these organisms (life in the generalised sense: "city-life", "life on the street") then it is reasonable to conclude that life itself has no concept of fairness as such, as life is not an entity with the ability to differentiate between fair and unfair. This point alone undermines the whole statement "life isn't fair", as not only being a poor excuse for the cruelty / evil of humanity, but a poorly structured idea that is mistakenly trying to personify a concept that is unpersonifiable.
Even the "natural evils" - earthquakes, tsunamis, famine, etc... cannot be seen as examples of "life not being fair", as such events are often random occurences, and their impact on human life can often be as much due to the responses and help efforts of humanity as the severity of the events themselves.
In short, when somebody tries to tell you that life isn't fair, they are hiding their own and the human race's inability to all be fair to one another behind the scapegoat of no responsibility, nature itself.