Sometimes I think agnostics claim to be agnostic based on a false or skewed definition of atheist.
As an atheist I view the concept of a god as illogical I also see that I cannot know a god doesn't exist. I never claimed to know god doesn't exist I simply do not have belief one does.
atheist : one who lacks belief in a deity
I was not aware I had to know a god doesn't exist in order to be atheist.