Regarding this, I will like to draw your attention to the following article.
Atheism | Naturalism.org
That article states :
The articles in this section place atheism in the broader context of naturalism, suggesting that atheists might profitably expand their horizons beyond mere disbelief into a positive endorsement of a naturalistic worldview. Atheists strongly identifying as such, or those not in a market for a comprehensive worldview, will decline this invitation, which is fine.
In other words, atheism and philosophical naturalism are not the same. Regardless of that, no-one speaks for atheism as a whole anyway. Some atheists would like to think they do, no doubt.
Regarding Dr. Gleiser ‘s view, his statement about atheistic stand “I don't believe even though I have no evidence for or against, simply I don't believe.', suggests that he is not conflating. At least, I think so.
Dr Gleiser can make whatever claims about atheism he wants. But all science starts with a hypothesis. That is not problematic. It's problematic if that hypothesis impacts on the methods and conclusions drawn.