Is gnostic atheism ironic?

[CleanShavenJesus]

I haven't made a topic in a while, so I may as well post this up.

I idenfity as an agnostic atheist (and a Dudeist on the side), if you did not know, which means I don't believe in God but I'm not 100% certain that I'm right about that. Which, to me, is the most logical position to take on the subject. Many debates I see on this site and in real life between theists and atheists is, "Theist, how can you be so sure about your belief? How do you know you're right?" Yet, sometimes this argument comes from a gnostic atheist or an atheist that claims to be 100% sure about their atheism.

I don't understand that. How can you be 100% knowledgable that there's no God? It makes as much sense as being 100% knowledgable that there is one. You can't know. That's why I think gnostic atheism is just ironic. Fighting against the illogcal position of complete knowledge of a god while claiming to have complete knowledge that there isn't one. It doesn't make sense to me.