From what I'm understanding, They do not reject subjectivity entirely. Of course it exists. I believe, perhaps, that they are just stating that subjectivity may not be the most effective pathway to determining fact from fiction and that there are other means which are more effective.
Well, that wasn't a very accurate representation of the discussion.
The facts say that atheists request evidence for God and the soul (substituting subjectivity for objectivity), they regard love and hate as electrochemistry in the brain (substituting subjectivity for objectivity), they deny free will, and deny any choosing occurs in the universe, intelligent design / creationism (as subjectivity operates based on choosing), they understand truth as interchangeable with fact (throwing out the subjective importance part to truth), they define subjectivity in terms of uniqueness not freedom (to avoid real subjectivity).
In the presence of the reality of the commonly human head vs heart struggle this can only mean one thing, that atheism represents a sophisticated attack on subjectivity.
It is very obvious that a very large share of atheists are devoted to truth, as meaning only fact, to the exclusion of any and all subjectivity. That is their first commitment. Then as a matter of scientific enquiry they may, or may not, look at how subjectivity functions, just like they look at any other phenomenon in the universe, like photosynthesis, the boilingtemperature of water. They regard subjectivity as just one more thing among many which science will also deal with, and not as fundamental to their understanding of things. This is because of their overriding commitment to fact.