The solipsist is said to be the ultimate skeptic. I suppose there are worst ways to end up.
Who was claiming atheism is scientific? Atheism is a choice to not invest belief into any God. For me, not having a good enough reason to believe in any particular God. So while you can say it's wrong for you it is not wrong for me.
Science only validates what is claimed. The only claim
atheism makes is that someone lacks a belief in any God. Atheism is atheism by definition not through scientific validation. The definition being what it is, it is not anything under dispute.