Vlad is desperate to show that atheism is a fully fledged belief system, with a burden of proof. This is designed to let him off the hook vis a vis his own beliefs.
I think there are atheists who are committed to the idea of a God-free world, but many atheists are not like this. They are agnostic atheists, where 'agnostic' refers to not knowing, and 'atheist' to lack of belief. The ones with a commitment are presumably gnostic atheists, that is, a 7 on the Dawkins scale.
It also seems odd to tell people what their beliefs are - "you are, in fact, committed to X and Y". Hang on, that's for me to decide.