At it's core, atheism is not an active position, it is merely a passive position. 2 atheists can have nothing in common other than that they don't believe in a god. There can't be a dogma as there are no teachings or philosophy where things like religions are built around. However, some people tend to take things a bit further and actually establish a philosophy which might be dogmatic.
What I think you are refering to is the faulty idea of some religious people that science is some sort of religion in itself. However, given that science is built on the basis of falsifiability and correcting itself, a dogma is inherently absent. Nothing has to 'just be accepted' as there is (or will be, in the case of some of the newer theories) justification behind everything.