Hitchens’s razor is an epistemological razor expressed by writer Christopher Hitchens. It says that the burden of proof regarding the truthfulness of a claim lies with the one who makes the claim; if this burden is not met, then the claim is unfounded, and its opponents need not argue further in order to dismiss it.
Hitchens has phrased the razor in writing as “What can be asserted without evidence can also be dismissed without evidence.” But atheism is presented without evidence. Thus, using Hitchen’s own protocol we can dismiss atheism.
The main rejection to this will likely be that atheism is not making a claim, so there is no burden of proof. Which is the only way that the atheist can accept atheism without any evidence and be epistemologically consistent.
The phrase “God exists” is either true or false, and atheistic worldviews do not include a God. So I think we can reasonably conclude that atheists believe that God doesn’t exist, whether or not they care to defend that position with evidence.