because we fear absurdity.
the problem is that since the dawn of time we have always looked at life and death as opposites. and death becomes the negative, the bad, the evil. life, obviously, becomes positive, good and right. but its not. esoteric wisdom tells us that life and death are one as are all the seeming opposites in this world. light and dark, man and woman etc. but we have opposites and one side is good and the other is bad.
death is tricky because we lump it up with "end" which is another negative and make it even worse. almost ANYTHING that is bad then automatically gets placed in the same corner as death. thus life is everything and death is nothing. life is good. death is bad. life is joy. death is sorrow. life is light. death is darkness. life is beginning. death is the end. and so on....to the point that we just want to separate from this negative half of the binary opposition as much as possible. because we don't want our lives to "end". human ignorance prevents us from seeing that like all opposites, end and beginning also go hand in hand and are inseperable.
the funny (and tragic) thing is that in avoiding death we are avoiding the inevitable. death can't be escaped. in trying to preserve life, we are going on a doomed expidition because death is its counterpart. one can't live without the other. thus what should really be "an end to one phase and the beginning of another" is simply seen as "the end". period. and to escape this inevitablility we keep looking for ways to go on living. to preserve ourselves and our lives.....just because we keep seeing the world as something split in halves, one of which is good and the other as bad.
so we have to seek to give meaning to our life for it to remain good (and so on the positive half) because "meaningless" is in the same corner as death. why we look for meaning to life is to keep it on the positive side of the dichotomy because we just don't understand that life and death are one and the same. there is meaning and truth in everything but we only try to see it in the positive halves. ironically these halves even exist.
btw, that's the same reason we try to give death meaning too. that's our last ditch attempt to try and wean over death into the positive side
~Sado