This will be a response to Sung Min’s post, found here: https://esmancientgreeks.wordpress.com/2015/04/18/purpose-of-nihilism/.
Overall, I agree with many of your points and whole-heartedly disagree with nihilism as a philosophy and concept. I would like to question some of your finer points on religion vs. spitiuality and what gives life meaning.
Religion are spirituality are not equivalent. It is possible for one to believe that there is a higher power- something that acts like God to some people- and not follow any particular religion. It is also possible for one to not believe in a higher power and not follow any particular religion- what most people call an atheist. Finally, it is possible for one to believe in a higher power and to follow a particular religion. My argument lies with the first two groups of people. For the atheist, one argument that can be offered is that there is no God or gods because they have not experienced either. These people can be, for all intents and purposes, very happy, leading a life where they do not believe in any sort of afterlife. This is where your argument weakens: happiness is subjective. What can make one person happy can cause another suffering. There is a positive correlation between spirituality and happiness, but we don’t know how to design an experiment to test that.
My question for you is: how can one experience God? Is it more of a Dionysian phenomenon where it cannot be explained? Or can it be written down with certainty? My stance is that experiencing the touch of a higher power of sorts is something that cannot be explained, but one knows it when one feels it. This brings to mind another blog, 13.7 from NPR, since they recently discussed the concept of higher powers in two articles: A God That Could Be Real in a Scientific Universe and A New Way To Think About God. I encourage you to read those posts. These leave room for the other sort of people: the spiritual but not religious.
I put myself in that category. I do not live my life to glorify a higher power. I feel part of my purpose in life is to care for others in their times of need. That invigorates me, so that is how I live my life. I entertain the idea that there is a higher power that I can connect to and experience, but I do not live solely with that higher power in mind. The differece between spirituality and religion is vast and should not be confused.
As far as life purposes go, people are sometimes just told what to do, so they do that. Other times, people simply do not feel like they have a purpose in life, and they do not try to find it. That is, in my opinion, where nihilism comes in. Those who cannot find a purpose go about their day believing that the world is useless and that there has been nothing and will be nothing. Again, I cannot claim to know how a nihilist might think because I am not one.
To answer your confusion with people rejecting the world as worthless, those people may have had traumatic experiences or feel like the world has cheated them or have experienced enough that they feel like there is no more to experience. Beyond those possibilities, I cannot answer more of your questions.