Interesting that so many English learners seem to choose the heaviest content. This statement is a philosophical one, one that asserts humans have inherent worth.
It applies to us too. We shouldn't treat ourselves as a means to our own ends.
The set phrase "means to an end" and its variations describes a methodology or resource used to accomplish some other goal. In this case, the "goal" is death, or the end of life. The author is asserting that we should not see ourselves as a mere "ticking time bomb," so to speak, waiting to die with no greater purpose in life. This nihilistic view would leave no reason for us to not kill ourselves early in life, or become completely hedonistic (pleasure-seeking) and kill ourselves in a slower way through vices. He is saying our lives have inherent value, and we should respect that and ourselves, avoiding self-destructive behavior.