Hereby my reply, as requested, for why I am an atheist. My name is Maarten-Jan and I’m from the Netherlands.
Since I was a child, I was always interested in learning new things. I loved reading. Fiction was a big part in it, but I also had several science for kids books, about astronomy, insects, history and more. My upbringing was more or less catholic light, I went through all the steps of becoming a catholic, but me and my parents rarely attended church. I believed in god back then.
My first ‘rebellion’ against the church was when I was 11. I had to go through the process of confirmation: I hated every step of the way. From what I remember, this was not because of a crisis of faith or something, but mostly because the whole process was freaking boring. I never liked going to church, and in this confirmation period, I had to attend church-like meetings every week.
I remember fighting with my parents about it, and I believe in one of those fights I proclaimed disbelief in god. My parents only pressed the matter of my confirmation because of their view that if you start something, you have to finish it. They did not put my little sister later on through this terribly boring process. I can’t remember if my claimed disbelief was real, or just to upset my parents. I do remember it was not the big issue.
When I went to high school, religion faded into the background. I attended church once a year, with christmas, and that was mostly it. I never really thought about it, I just hated going to church because it was boring. Because I went to the Gymnasium, I got in contact with the old Greek and Latin language and mythology. I loved these old stories of gods and heroes.
In the second part of high school, literature became a huge part of the curriculum, with regards to the Dutch, English and German classes. I remember that my Dutch teacher discussed the relation of literature to the views of the people of the time, and the use of old themes in mythology is prevalent in literature. He labeled the Christian faith, with the side note that not everyone agreed with him on this, as a mythology as well. I immediately recognized this to be true. From this point onward, I consciously rejected christianity as a whole and the belief in a god.
Because I went to a secular school and my very mildly religious parents, I believed for a long time that the whole world believed more or less like I did. When I finished high school, I went on to the university. I educated myself on evolution (I dropped biology in the second year of high school, evolution was in it, but not a big part of it), and I got to read the God Delusion of Dawkins.
Through youtube, I got into contact with Thunderf00t (and the WDPLAC) and AronRa videos and eventually the atheist experience. I realized there were a whole lot of people that disagreed with me (and held really idiotic beliefs). Furthermore, I got the words to define my belief as a secular humanist, atheist, antitheist, rationalist and free thinker.
Ironically, I only learned of the dogmas of catholicism when I was already an atheist. I was surprised and frankly horrified that so many people actually believed that stuff, and that no-one ever told me about this when I was in the church (although that may not be too surprising, considering their goal of keeping people in the church). The only thing I got back then was the happy story about Jesus, forgiveness, et cetera.
From that point forward, I became an active atheist, I argued a lot with my parents and online, I read several books on the subject, watch hundreds of youtube videos, and got to read Pharyngula. I am continuing to argue, test my beliefs, and learn new things until this day. My search for the truth, the whole truth and nothing but the truth will hopefully continue throughout my life.