Why not? You believe people should just live, maybe preparing for the afterlife is a form of living for some people. Some people live to sing, some people live to race (any kind of race) some people live to love and some live to prepare for the afterlife. What is so wrong with that?
If it were simply "some" people, then I would undertsand it. However, it is not some, it is nearly all people. Most people are taught that they must either fear death, or live a life that is considered worthy enough to be continued in some sort of afterlife, whether through Heaven, or reincarnation. From the egyptians and their lives spent building pyramids, to modern religion, spending life preparing for whatever may happen after death is ingrained into us.
What's the point of living if we don't care about living?
Living for the joy of living, for the inescapable ups and downs, the acknowledement that life is for... well... living, that isn't caring about living? It's actually quite the opposite. In living as I described it in my original post, yes, you would have think about the moments to come. It's inevitable. However, people are thinking beyond their current life, into an afterlife. If we can't enjoy and take advantage of living this life, (the one we know for certain we have), then why do we deserve any kind of afterlife?
Animals really have nothing to do with my point, as they don't spend life obsessing over their death, and what may happen afterward.